Jack is Founder and Managing Partner at Alt Capital, an early-stage venture firm with $425M in assets under management investing in B2B software and hard tech startups. He previously co-founded Lattice, an HR performance management platform that scaled to a $3 billion valuation serving thousands of global companies.

Jack graduated from Princeton University with an A.B. in Economics in 2011, then worked as VP of Business Development at Teespring and as an Investor at Hydrazine Capital, which he co-founded with his brother Sam Altman in 2012. He co-founded Lattice in September 2015 and served as CEO until January 2024, when he transitioned to Executive Chairman.

Jack has invested in notable companies including Figma, Rippling, Writer, Vanta, and Flexport through his angel investing and Alt Capital portfolio. He hosts the Uncapped podcast where he interviews leading venture capitalists and entrepreneurs about building companies and investing.

Alt Capital launched its first $150M fund in February 2024 and raised a second $275M fund in just one week in September 2025. The firm takes a founder-first, conviction-driven approach, writing checks from $1M to $25M from inception through Series A, and has built a portfolio of 40+ companies in two years.

Under Jack's leadership, Lattice grew from a Y Combinator Winter 2016 graduate to serving over 2,500 companies including Reddit, Coinbase, and Asana, raising over $330M in funding. Alt Capital has quickly become a preferred co-investor for top-tier firms like Sequoia and Y Combinator, positioning itself as a go-to firm for ambitious founders building category-defining companies.