Michael Seibel

Michael Seibel (born October 7, 1982) is a partner at Y Combinator and co-founder of two startups – Justin.tv/Twitch and Socialcam. He first joined Y Combinator in 2013, advising hundreds of startups, and has been active in promoting diversity efforts among startup founders.

Education & Startups
Seibel was born in Brooklyn and calls New York City his favorite city. He moved to East Brunswick, New Jersey as a pre-teen and is a 2000 graduate of East Brunswick High School. At Yale, he majored in political science and became friends with Justin Kan. After his graduation in 2005, he worked as a finance director for Kweisi Mfume's unsuccessful run for the U.S. Senate in 2006. He then moved to Silicon Valley to co-found Justin.tv, and became CEO at the company (from 2007 to 2011). He then became CEO of Socialcam, a social video-sharing app that launched in March 2011 and sold to Autodesk for $60 million in 2012 (after existing for only 18 months). In 2014 Justin.tv was renamed Twitch Interactive and later that year sold to Amazon for $970 million.

Startup Mentoring, Y Combinator, Investments, Board Seats
In 2008, Michael Seibel was a key mentor to the co-founders of Airbnb and recommended them to Y Combinator.

In 2013 he became a part-time partner at Y Combinator and joined Y Combinator as its first African-American partner in October 2014. He became CEO of the Y Combinator Startup Accelerator in 2016. On March 15, 2024, Seibel announced that he was stepping down from his leadership role at Y Combinator after 8 years and returning to his original role of partner.

Some of Seibel's personal startup investments include Cruise, Brex, Figma, Rippling, Reddit, Clipboard Health, and Promise.

On June 10, 2020, it was announced that Seibel was named a Reddit board member, replacing Alexis Ohanian, who resigned on June 5, 2020, in response to the murder of George Floyd. In his resignation announcement, Ohanian had urged Reddit's board of directors to fill his vacant board seat with a black candidate. Reddit later named Seibel as the "first black board member in the company's history".

On December 15, 2020, it was announced that Seibel was named to the Dropbox board of directors.