Larsen Jensen is a venture capitalist, Olympic medalist, and former Navy SEAL. He is the founder and Managing General Partner of Harpoon Ventures, a San Diego-based early-stage firm with approximately $450 million under management. Since 2018, Harpoon has had numerous successful exits, including Airplane, Bluesky, and Truera. Its portfolio currently includes numerous defense and space technology companies like Astranis, Aalo Atomics, and Starcloud. 

I sat down with Jensen to discuss the defense tech ecosystem, his military service, and how to deal with challenges. What follows is a transcript of our conversation.

CB: Would you say that swimming was the formative experience in your life?

LJ: It for sure was. The obvious reason is that it was the first time in my life that I saw the direct correlation between hard work in and high performance out. Learning that at an early age is extremely important. I try to instill it in my kids. Small things compound over time. It's hard to find that lesson anywhere in life, and to experience it as concretely as you do in swimming.

Swimming is a time-based sport. Your time is your time. You know if you're good or not based on what your time is. It's not like gymnastics scoring or diving scoring, or team-based sports, where you could have a great pass but maybe someone doesn't catch it.

CB: At what point did you decide to take it to a higher level, where you were training for and entering the Olympic team?

LJ: It's a good question, because I'm not so sure if it was a decision or circumstance. I think it's actually a combination of both.

I started swimming relatively young compared to my peers — compared to the Phelpses and people like that, who ended up being my peers at the tail end of my career. But I didn't start doing year-round swimming until I was in high school.

It was probably junior year that I really came onto the scene. I think it was between my sophomore and junior year that I made my first nationals. I was fortunate that I earned rookie of the meet at that event by finaling in a couple of events, which is sort of rare for a first-time person who goes to nationals.

And then I believe it was my second nationals where I made my first international team representing Team USA, which was traveling to Japan. I still remember my mom, in her wisdom, getting me a passport. I'd never been out of the country. I grew up in a rural area in Central California — my parents were almond farmers. Fortunately she did, or else I wouldn't have been able to go to Japan for my first international competition. And that's when I was 16 years old.

So around that time is when it became evident that swimming was something I was pretty good at and had worked hard at. And just for context: if you make the national team for any of these international competitions, it's the equivalent of making the Olympic team in terms of the tryout process. But the pressure at the Olympic trials is a whole other level.

CB: How do you feel before you compete at that level, where a single performance decides whether or not you get to go and do this incredible thing?

LJ: Jumping ahead a little bit — it's probably the same way as when you go into something in the military. You trust your training, you know you're well prepared, and you don't hope to rise to the occasion. You plan to fall back on your training. So much of it is muscle memory, so much of it is preparation. It's definitely nerve-wracking, but also exhilarating, and something that I very much crave and I miss.

CB: How do you compare Athens and Beijing? I know the latter had a little bit more of a geopolitical bent to it, with China's rise.

LJ: My first Olympics being at the birthplace of the modern Olympic Games in Athens, Greece, was super, super cool and really historic in that regard.

On the other hand, going to China for what was effectively their coming-out party — it was when they were starting to resurge as a leader on the global stage. It was much less obvious then, compared to now, 20 years later, that they would be potentially our only economic competitor and potential adversary on a global scale. It just felt like they were coming onto the scene, and they invested — at least at that point — more than any other country had done in terms of putting the Olympic Games spectacle on for athletes and spectators.

I did better in 2004. I got to chase after Grant Hackett, the world-record holder. He set the Olympic record for that race, the 1,500-meter freestyle. My time was right around there — I lost by a second and a half. I look back on that almost like, you know, in Rocky, going the distance. I didn't win. Rocky didn't win — and then Rocky won. But he went the distance with Apollo Creed, and I look back on that as: I went the distance with the greatest distance swimmer of our era, Grant Hackett. And I'm really, really proud of that.

2008 was unique for a whole lot of other reasons. It was my last Olympics. It was actually my last race. I knew I was going to be done after that. So that's sentimental.

CB: You had the Winklevosses there too, right?

LJ: Who would have thought, right? It was a really formative Olympics for many reasons. I had the opportunity to meet President Bush and all that, and I got bronze, which I'm super proud of — but never had the United States flag fly and our American anthem play for us, or for me. But I got to witness Michael Phelps and be a teammate to him and a bunch of those folks, and I actually became pretty good buddies with the Winklevoss twins during that Olympics as well.

At the time I didn't really know that they originated and started the Facebook idea; the movie came out later. I remember spending some time with them in New York a few years later; I think I had finished SEAL training at that point. And they're like, "We're going all in on this thing called Bitcoin."

CB: Did you buy some Bitcoin?

LJ: I really didn't. I wasn't really in the tech investing frame of mind at that point. I was getting ready to deploy to Afghanistan. We all have regrets; not listening to smart people in my orbit at that time is probably one of them.

CB: Obviously, you dedicated most of your energy to swimming for years. How did you decide to call it? That's got to be pretty emotional, to say, "All right, I'm done."

LJ: Yeah, it is. For better or worse, I have never really had a problem with that. I've always been okay walking away to start the next adventure and to dedicate myself toward the next thing — at least as it goes from swimming to the SEAL teams, and from the SEAL teams into tech. I've never really had difficulty going back and having remorse about that, or wanting to go back and have a comeback in swimming.

I think that's something that I've been fortunate to have in me, because I know it's not always the case. A lot of people, whether it be special operators or military folks or athletes, struggle to find that next calling.

And it was very hard for me. Probably the hardest for me was leaving the military and going into the private sector, and feeling that sense of camaraderie, self-worth, belonging, accomplishment all over again. It's a lonely feeling. So it was a tough couple of years until I really found what I feel like is my third and final career act.

CB: How do you compare the challenge of training and competing at the high end of the Olympic level with military training, things like BUD/S? Is it a different type of challenge?

LJ: I wish I could give you an absolute answer and say one is for sure harder than the other, but I don't think that's accurate.

I think swimming is harder, in my experience, because of the time duration you have to put into it before you have any sort of positive feedback. It's every four years between Olympics. In the case of swimming, you're waking up at five, hitting the pool at 5:30, sometimes even earlier, and swimming for a couple of hours. Then going to class and all that stuff, and coming back and getting after it again for another couple of hours. And you just do that day in and day out, week in and week out, month in and month out, year in and year out, to get ready for one race — which you may or may not make.

That takes a lot of dedication and focus. Football players do a game every Sunday. Swimmers have years before our equivalent of the national championship or the Super Bowl. I think a lot of guys, myself included, struggled with that.

From a SEAL standpoint, going through BUD/S: nothing's harder than Hell Week, to me, in terms of any of the training that I did for the Olympics. We definitely had hard workouts, hard weeks, hard months, hard years — but just the raw intensity of doing a week straight, effectively, of three to four hours' total sleep for the entire week, and being physical the entire time. It's a meat grinder, and you definitely have to earn it to make it through and earn the SEAL Trident. So that's probably the hardest singular event that I've done — Hell Week, from a physical and mental conditioning standpoint. But the duration is just a whole other animal when you're competing to make the Olympics.

CB: How does that sleep deprivation and training translate to actual combat, actual deployment experiences?

LJ: Turns out no sleep is bad for you, man. That's not good.

But I think it translates pretty well, because you're training for a worst-case scenario. You're training for a scenario that, unfortunately, many brave people have encountered, where you're on ops for a long period of time and the worst happens, and you lose guys, and you have to be prepared mentally, physically, emotionally to navigate through that and never quit, even when things are really, really bleak.

And so Hell Week is a microcosm of that. That is not the norm — that level of sleep deprivation and having to perform at an elite level week in, week out, or through the course of an entire combat tour. But you're preparing yourself for the worst, and always having that in the back of your mind: that you've been through something extremely arduous with people who have also been through it with you, who you know you can trust and depend on. They would rather die than leave you behind, and would rather die than quit. And you need that when you're going into harm's way — that mutual trust, not only in your peers, but in yourself.

CB: You jumped into the service at a very interesting time, halfway through the Global War on Terror, during a technological renaissance where digital was being integrated into the battlefield. I'm assuming they trial a lot of new tech on the SEALs. What did you learn about tech in particular from your military service?

LJ: I felt this huge debt of gratitude to have the opportunity to represent our country on the international playing field and at the Olympic Games. And I felt like I had to do something to give back to my country.

And we were also in a time of war. Who would have thought how long the conflict was going to go on? It went on for almost 10 years after I went in, in '09. So it sounds a little bit ridiculous, but I thought I had missed it. I thought I had missed the opportunity to sign up and serve in combat alongside some of these battle-hardened warriors. But in hindsight, we were only sort of halfway through.

I don't even compare myself to them — I'm not at all a battle-hardened hero like the guys that I served with. But I was lucky to have many people in my platoons, and training us, who are among the most decorated veterans of our era. So it's really a humbling thing to be a part of.

But as it relates to the technology component: we didn't really have a lot of the things that we're now developing in the tech ecosystem, and we fought against a rather non-technical enemy, and they were still extremely effective against us. Elon had a quote the other day that I actually disagree with — that technological superiority is the single determinant of warfare success broadly. I can see the point, but the enemy always has an opportunity to adapt. And interestingly, they did it quite well there, with IEDs and insurgent tactics that overmatched our technological superiority in many ways, and just made it into a long, drawn-out conflict where there was no smooth off-ramp.

So we had total technological superiority: Predators, Reapers, total air superiority, night vision, optics, way better training, way better conditioning, way better diets. You name it, we had it. And the enemy — being Al Qaeda or the Taliban — didn't have any of that. But that doesn't mean they weren't tremendously successful against us, to the point where we all saw the Afghanistan withdrawal. That was pretty embarrassing.

So out of that experience — and seeing in some ways the things that we had right, that were super cool, and every little boy's dream to get to use, shooting guns with lasers on the end of them with night vision; I mean, it's super badass — but at the same time, we also had a lot of legacy technology that seemed to be from Gulf War One that we were using. That experience, plus that curiosity, is what drew me to the tech ecosystem in Silicon Valley, to see what the frontier of technology really was, and how that would impact not only the defense ecosystem but also our economic standing and geopolitics broadly.

And what I found was exactly that: that this modern era of technology was going to have much higher consequences than I think anybody else realized. The new space race that we have — thank goodness we have SpaceX and Elon. The nuclear renaissance that we have now to bring energy abundance online. The AI race that just keeps accelerating on a daily basis. It's a remarkable time we live in.

CB: Did you use Palantir Gotham?

LJ: We did. On my second rotation, I managed a cross-functional intelligence team, so that was part of the suite of products that we used. Obviously it was extremely effective. It really reduced the man-hours — the number of people that we needed to synthesize information into actionable intelligence for targeting purposes.

Back then, I think it was really the only notable defense tech company. There really wasn't anybody else that was venture-backed that I knew of at the time that was making a difference in that space. Lots of smaller technology vendors that had point solutions, but nothing that was really making a holistic improvement to how we did a core part of our mission.

CB: How did you make the leap from military service to being a VC?

LJ: I think it's very similar, actually. At one point I woke up and said I wanted to be an Olympian. At one point I woke up and said I wanted to be a Navy SEAL. At one point I woke up and said I wanted to be a VC. I could probably read into all of those decisions and give you logic and reasons, but there was just something that called me to want to do those things.

I had some friends of mine from undergrad who were startup founders — they had started a company and sold it and done well — and they started to educate me about the tech ecosystem, what venture was. And I just became enthralled with the concept of investing in innovation, and investing in people who are brilliant folks, who are the Navy SEALs or Michael Phelpses of their domains, and being their partner in some capacity.

So in a lot of ways, I think the way I have learned to find my sense of belonging — just like I did in the swimming pool with my Olympic team, or in the SEAL teams with my team of other operators who were going into harm's way — is to be that teammate to founders who are equally audacious and trying to win their version of a gold medal. And most commonly not because it's financially lucrative. It's just because they want to win. Nobody swims for an Olympic gold medal to make a lot of money. They just want to be the best, and they dedicate their lives to being the best. And I see that in the founders that we invest in, or that we're trying to find. There's something raw and ultra-simple about that that's exciting to me.

CB: We were talking a little about psychology earlier. How do you compare the challenge of placing a high-risk bet — where you stand to lose maybe a lot of money — with the other risks you've taken? Is it a different psychological profile of risk?

LJ: 100%. It's way different.

CB: It's not physical risk.

LJ: Yeah, it's not physical risk. In the military, we mitigate risk as much as we possibly can. There are go/no-go criteria for every single operation. You have contingencies for every phase of the operation. You train to it. And still, edge cases occur, and the enemy gets a vote.

So I actually think that preparation process is well suited for venture. We mitigate risk as much as we can, but different from the military, we need to take more risk in venture, because the losses don't matter — it's how big the winner is. You sort of know how big the payout could be on a bin Laden raid — which I was never a part of, but fortunately I had some buddies who were. You know what you're going for. That's the unicorn op. That's the payout. And you obviously don't want anything bad to happen to anybody.

But in startup world, there is an unknown upside when things go well that you just can't forecast or predict. And I think we need to be more risk-seeking as venture capitalists and as entrepreneurs, and I myself need to be more risk-seeking with that, because only by investing in people who are truly special can you have the creation of these world-changing companies. So that's something that we talk about every single day as a team: how we can be more risk-seeking while also making sure we mitigate things that could go wrong as best we can — just like a combat operation.

CB: With the Global War on Terror, and then now with Ukraine and the war in the Gulf, we've started to see a really profound change in how wars are fought. As a former SEAL and as somebody who's actually investing in these companies — what's really happening in warfare? What are the major trends that we need to understand to appreciate what's happening right now?

LJ: I think the Russia-Ukraine conflict is going to go down in history as Drone War One.

A number of years ago, when all of this started, it was interesting to see how necessity became the mother of invention. Ukraine lost a lot of soldiers, had depleted all its stockpiles of conventional weapons, and by necessity they started arming hobbyist drones and flying them as far as they possibly could to take out Russian artillery, tanks, armored personnel carriers, etc., with surprising effects to many folks.

Some friends of mine had deployed in the fight against ISIS in Iraq. At that point, ISIS was basically taking what they learned from buried IEDs on the road and getting DJIs and putting grenades on them and dropping them on guys. That's a natural progression of the IED threat, because hobbyist-grade electronics and drones got good enough that you could do that.

Ukraine put all that on steroids, and it wasn't just dropping a grenade here and there with limited effects — it was catastrophic effects, where you have something that costs 1,000 bucks taking out a $10 million radar site. That asymmetry was extremely fascinating to me.

What we would previously think of as insurgent-like tactics or techniques that were used against us during GWOT have now been scaled and adopted by conventional forces. The United States is leaning in and doing what I think we do best — we're finally getting to the scale game.

My view, and the view of all my buddies who served, is: this is just going to change war forever. There'll be something that changes it forever after this, but at least for now, for our generation, it's this new capability of attritable mass unmanned systems of every single form factor — whether it be UGVs, UAVs, USVs, UUVs, you name the Vs.

These things are going to change how everything works. Not because they're stealth bombers and super exquisite, but because they're so cheap, so hard to deter or to interdict — and even if you do, you've got potentially 100 or 1,000 more right behind where that came from. So instead of building $100 billion in stealth fighters — I mean, how many small drones can we have for $100 billion?

CB: Quite a few.

LJ: How do you stop all of those? You just can't, because you need millions of air defense rounds to interdict every single one of those, and you're not going to hit every single one of them.

And the other thing that I think is really interesting and has changed a lot is: this doesn't take a nation-state to adopt this capability. You can have rogue actors, small terrorist cells, that unfortunately can very easily create these capabilities. And so the threat aperture is much bigger than it ever was.

CB: Did you see that the Houthis basically vibe-coded software for guided missiles with Claude?

LJ: I saw that. What do you even do with that?

CB: As a Navy guy, what's your thesis on USVs? I know you're invested in Ulysses.

LJ: We try not to have a thesis, which sounds a little bit reckless. We want to meet impressive people who enlighten us into a future version of a world that they want to create. So anything that I would say is just paraphrasing something that any one of our founders has told us that we fell in love with.

But zooming out from that a little bit: I think we're just going to see this across all domains. We're going to see this in space, in the air, on the ground, on the surface, subsurface. And I think we're seeing it in cyber as well — if you consider AI agents that can self-spawn dozens more AI agents, I think it's sort of the same thing, just in a different domain.

So I think that's where the future of war is not only going, but where it is. It's just much higher fragmentation of assets. How many GPS satellites do we have in our constellations? Something like a dozen, two dozen. It's not that many, and those are really, really important to the entire economy and to how everything navigates on Earth. So I think we need resilience with space assets, resilience in communication, and we need to not have these big juicy targets up there anymore that are easy to attack.

And the same thing for aerial platforms, same thing for surface vessels. The core of our entire Navy is built around the carrier strike group. That's a very big singular target, with lots of people and lots of equipment on it. How do we start to diversify against those big juicy targets into a new version of the aircraft carrier that carries unmanned systems? That's inevitable. I don't have any inside scoop on that, unfortunately. But I wonder why we don't have that yet. 

CB: I think the Iranians had one and we sank it.

LJ: Exactly. Why don't we have those at scale? How much does an aircraft carrier cost? Just to make it up, 10 billion bucks, something like that, something crazy. Why don't we have dozens of these unmanned carriers?

And we're working toward that. I know DIU has put out solicitations, and Saronic is building toward some of these things — USV-launched effects and air defense and stuff like that.

Some will render our existing systems obsolete. I think we're probably going to need fewer Javelins, as an example, because they've got, what, like a five-kilometer effective range, and you've got to have line of sight to the target. They're expensive on a per-shot basis. Do we need that, when we've got an FPV that can go farther and is more accurate, and can go around a building and hit somebody behind it?

Natural selection will take place. But in other cases, I think it just increases the amount of capability and arms that we're going to need as a nation, and that we're going to have to contend with against our adversaries.

CB: From an investor standpoint, where's the revenue going to come from in this new space? What's the actual business plan long term?

LJ: Well, very obviously, Uncle Sam is the buyer for all of these defense articles. But the challenge that I think some of the newer entrepreneurs are walking into is the buzz saw called continuing resolutions, which don't provide for any new starts for new technologies. And for better or worse, I've been at this long enough to have seen that happen.

If and when the House flips this November, what does that do to us passing a budget that allows for these new technologies to be funded and brought online? There's a whole political aspect of this that I think people are underestimating, because it's one thing to get a contract, it's another thing to get it funded. A lot of times the customer doesn't have its budget funded because this is a new start, and so that requires them either to scrap something else they're working on or wait on Congress to actually pass the budget. So that's where things can get pretty precarious from a founder standpoint or an investor standpoint.

What I've really appreciated is that some of the old hands in the business, who have been doing defense tech for a while, are bolstering their balance sheets to be able to weather continuing resolutions for a cycle or two, and exploring international business as well, to sell to our partners and allies either on the Pacific Rim or in the Middle East. Less so in Europe, because I think fortunately they're rearming themselves and starting to have their own sovereign capabilities, versus relying on the United States.

That's where I see a lot of the more sophisticated founders going, versus relying on single programs from Uncle Sam — because those things can go away. A handful of years ago there was the $10 billion JEDI contract — it was a joint cloud contract, and that whole thing got scuttled. There were a few startups that were going for that JEDI deal, and that thing's gone.

So I think putting all your eggs in one basket can work really well if you get it right. But if you get it wrong — there's a continuing resolution, or money gets reprogrammed, or there's a new hotness that the military's behind and you're not part of that — things can get bleak pretty quick.

CB: Would you say any of these subsectors in the defense space are becoming oversaturated? How many different ways can you do the UAV play, for example?

LJ: Yeah, in many ways I think they are. But I also think that's not an indictment of founders, the department, or on venture capitalists. One of the great things that we have in our country is relentless optimism — millions of concurrent experiments occurring, with thousands of founders running these experiments. And only through that will you have the chance for a true breakthrough.

So needless to say, I don't think everybody's going to make it. Not everybody made it through the dot-com era. Not everybody made it through SaaS and cloud. But are we all better off as a society because of those companies that did make it through? And would we have had those companies if we didn't have that market dynamic to pull the smartest minds in the world into those segments? Probably not.

And also the counterfactual: we all know the SpaceX example, or even the Tesla example, where they were what, a month or two away from insolvency and bankruptcy? What would have happened if SpaceX was gone? We basically wouldn't have a space program, for all intents and purposes, in the United States. China would be eating our lunch. How many companies are out there that otherwise could have reached SpaceX-style scale and importance, that just didn't make it that extra month?

So I have the ultimate respect for the founders who are out there building for this. It's overly simplistic to say, "Yeah, we don't need another one." Maybe that's true — but maybe that kid who's dropping out of whatever school actually does have a breakthrough that changes everybody's mind in terms of what the future is.

So rather than dissuading people, I'd rather have people try to build in that space, if they can recruit an amazing team and if they feel like they have a technology that could change the game to protect the United States. But you're right, there's a lot, and with that comes a lot of noise, and it makes it really challenging.

I also think, unlike other segments, that this is not winner-take-all. One of our companies that I helped to start is an attritable defense prime — a neo-prime — called Vector. They were just an awardee in the second Gauntlet of the drone dominance program. I think a little bit of a contrarian take is that we're going to need way more of these things than any single company can provide. It's sort of like AI data centers — we just need more and more and more of it, and I think we're underestimating the volumes that are going to be required.

And I also know that the government as a customer doesn't like to be reliant on a single vendor. If you consider that in a Navy SEAL operation you have three contingencies pre-planned for every phase of the operation, Uncle Sam buys very similarly. You need that redundancy, or you're not prepared for when things go wrong — and things are going to go wrong.

CB: Have you been tracking the tech coming out of Ukraine, or even Russia, as this war has progressed?

LJ: More so on the Ukrainian side of the house, because obviously we can't invest, nor would we invest, in Russian-based capability.

But I think that's the benefit of rapid feedback cycles. In combat on the front lines, every day you're learning something new in a real-world environment. It's sort of like the Steve Blank philosophy for building a startup: stop whiteboarding and get out of the building and talk to customers, figure out what they actually need and what's going to solve a problem. There's no better example of that in defense tech than Ukraine.

They are iterating daily, weekly, monthly, to figure out how they overmatch the enemy — and the enemy is doing the same thing to them. And I think it's probably happening at a clip that we've never seen before. That's what's happening in Ukraine. And I think what we're seeing there is what we should be prepared for globally, unfortunately.

CB: Which of your investments has Harpoon had the most outsized impact on?

LJ: I should tell you a little bit more about Harpoon. We started a venture firm in the national interest. That's how to think about us.

Ten years ago, when I got into Silicon Valley, I was really lucky that the Andreessen team took a chance on me and gave me an internship, sort of sight unseen. And the same sentiment over at Lightspeed: they gave me a chance to be on the enterprise deal team and to learn from the best in the industry in terms of how they think about investing in next-generation technology companies.

But I couldn't help having that calling to serve again in a unique way. I saw what my friends were still doing on the battlefield, and wanted to contribute to our nation's greatness in some capacity again — not just in swimming, not just in the military, but now in venture and tech.

And so I saw basically one mission-aligned venture firm out there: In-Q-Tel. They'd been around for, at that point, 15 years — now it's 25 years — investing in capability for the United States of America. I'm like, well, we should create a private version of that.

So, similar to In-Q-Tel, we invest in these technologies that we think can move the needle for our country, and we help them open doors to break into the government market sooner than they might otherwise do themselves.

A lot has changed since we started that. Back then, there was a huge aversion, for a couple of reasons, to selling to Uncle Sam. Culturally, for sure, that was the status quo in Silicon Valley. Fortunately, I think that culture has evolved a lot. But also some really strong business reasons — sales cycles are really long, super lumpy customers. If you win, it's great. If you lose, it's bad.

And we've helped our companies close — we just did the tally the other day — $1.6 billion in government contracts that our portfolio companies have received, and we've had an outsized impact in all of those, which is really, really exciting. Ranging from literally me hand-jamming proposals, pre-AI, making sure they have all the necessary certifications and qualifications and all the paperwork required to start a federal business.

And our view is that if we're investing in the best technologists in the world, the best technologists in the world should try and serve our nation with their products and services — if there's a one-to-one fit. It's not a fit for everybody.

If I had just kept swimming and never signed up to join the military, I'd feel regret and remorse about that. I think increasingly a lot of founders are feeling that way too — that we should give back in some capacity, and if we have the best technology, it should go for the betterment of our country, to help save our service members' lives, or deter conflict, or give us a future of energy abundance or AI intelligence abundance.

And that's why we started our franchise, and what we try to do with our founders is to help them solve our nation's problems, not just business problems.

This interview has been lightly edited for length and clarity