# Zack Rosen

> Zack Rosen is the co-founder and former CEO of Pantheon, a website operations platform founded in 2010. His career began with open source organizing software for Howard Dean’s presidential campaign and includes CivicSpace, Chapter Three and Mission Bicycle. Based in San Francisco, he also co-founded California YIMBY and Abundance Network, extending his work into housing policy and civic organizing.

- **Role:** Co-founder at Pantheon; co-founder at Abundance Network
- **Organizations:** Pantheon, Abundance Network, Abundant SF, California YIMBY, Chapter Three, Mission Bicycle, CivicSpace
- **Education:** Studied computer science; left without completing a degree, University of Illinois at Urbana-Champaign
- **Known for:** Co-founded Pantheon and led it as CEO for approximately fourteen years., Pantheon’s July 2021 funding announcement reported over 12,000 customers and 2,500 partners., Co-founded California YIMBY, which has advocated for state housing reforms.

## Career timeline

- **2003** — Left college to work on Howard Dean’s campaign and DeanSpace.
- **After the Dean campaign** — Co-founded CivicSpace; later co-founded Drupal agency Chapter Three.
- **2007** — Helped start Mission Bicycle with collaborators including Matt Cheney, Josh Koenig and John Adams.
- **2010** — Co-founded Pantheon with David Strauss, Josh Koenig and Matt Cheney.
- **2017** — Co-founded California YIMBY with Brian Hanlon and Nat Friedman.
- **2021** — Pantheon announced a $100 million Series E at a valuation above $1 billion.
- **2024-05** — Announced he was stepping down as Pantheon CEO, with Bill Ingram becoming interim CEO.
- **2024-11** — Sameer Kazi became CEO; Rosen and Roland Benedetti introduced Pantheon Content Publisher.
- **2025** — Publicly discussed civic organizing through Abundance Network and recruiting its founding software engineer.

## Achievements

- Co-founded Pantheon and led it as CEO for approximately fourteen years.
- Pantheon’s July 2021 funding announcement reported over 12,000 customers and 2,500 partners.
- Co-founded California YIMBY, which has advocated for state housing reforms.
- Co-founded Abundance Network with Misha Chellam.

## Latest updates

- **2026-10** — At research time, Pantheon’s leadership page lists Rosen as a co-founder on its board and Sameer Kazi as CEO; Abundance Network lists Rosen as a founder.
- **2025-09** — California YIMBY celebrated legislative passage of SB 79 and connected the transit housing effort to Hanlon’s 2017 conversation with Rosen and Friedman.
- **2025-02** — Appeared on The Great Battlefield podcast to discuss Pantheon, California YIMBY and Abundance Network.
- **2024-11** — Co-authored the introduction of Pantheon Content Publisher with Roland Benedetti.

## Links

- Website: http://zacker.org
- LinkedIn: https://www.linkedin.com/in/zacharyrosen/
- Twitter/X: https://twitter.com/zack

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Profile page: https://yespress.io/zack-rosen
Published by YesPress — https://yespress.io
Last updated: 2026-10-15