Harpoon Ventures closes $155M fund targeting defense and national security technology

Harpoon Ventures closes $155M fund

Larsen Jensen, founder and GP of Harpoon Ventures, is closing a $155M fund to invest in early-stage technology serving U.S. national security and allied interests — the firm's latest and largest since Jensen founded it in 2018.

The path to starting Harpoon was unconventional even by the standards of a sector that prizes military credibility. Jensen won a silver medal at the 2004 Athens Olympics and a bronze at Beijing in 2008 — both in the 400-meter freestyle — before completing SEAL training and deploying to Afghanistan. An early exposure to Palantir during his time in the teams gave him the technology conviction. He applied to Stanford's GSB, interned at Andreessen Horowitz before the program, then at Lightspeed between years, and left with the idea of building what he describes as a private-sector In-Q-Tel. Andreessen Horowitz and Lightspeed became Harpoon's first LPs.

“My name is Larsen Jensen. I'm the founder and GP at Harpoon Ventures, early stage venture capital firm focused on investing in technology and the national interest of the United States and our allies when appropriate. Today, we're announcing that we raised a $155,000,000 fund. We effectively said, hey, what if we could create a private sector In-Q-Tel? And that's what I set out to do.”

How the market shifted around the firm

When Harpoon launched in 2018, defense-adjacent technology investing was close to a fringe pursuit. Jensen describes attending Pentagon-area conferences and finding almost no high-caliber entrepreneurs or other venture firms in the room. The strategy then was largely dual-use: back enterprise software companies and help them navigate a government market their founders didn't know existed, covering cybersecurity, data infrastructure, and autonomy platforms.

The firm has since moved toward more explicitly defense-focused investing, tracking the broader shift in founder and engineering talent into the sector. Jensen says he has also stopped trying to impose a top-down view on what should be built, and instead focuses on identifying high-conviction founders with large visions.

Black Flag Accelerator

To move earlier in the stack, Harpoon launched the Black Flag Accelerator, targeting pre-seed and seed-stage defense and dual-use companies. Jensen says the firm now leads more rounds at that stage than it did historically, and credits the firm's growing brand in the sector as what makes that credible.

On whether genuine whitespace remains, Jensen argues both deep R&D bets and capability-delivery plays still have room — pointing to a still-undefined class of electronic or non-kinetic systems (he references public comments about a "discombobulator" used in Venezuela) as the kind of novel hardware he wants to back next.

The firm is based in San Diego.