Photo: TechCrunch, CC BY 2.0, via Wikimedia Commons ↗
About
Michael Seibel spent more than 12 years at Y Combinator, serving as CEO of its accelerator and as a group partner who worked with over a thousand startups, before transitioning to partner emeritus in 2025 with an eye toward public-sector work. He co-founded Justin.tv, which became Twitch, and Socialcam, and became one of the most recognizable startup advisors of his generation through YC's videos and office hours.
Contact· published on Michael's own website
Invests in
AI & Machine LearningDeep TechDeveloper ToolsFintechHardwareSaaS
Beyond investing
- Founded
- Co-founded Justin.tv, which grew into Twitch and sold to Amazon for $970m in 2014. Co-founded Socialcam, which sold to Autodesk for $60m in 2012. Seibel co-founded Justin.tv, which later became Twitch and sold to Amazon for $970 million in 2014.
- Education
- Graduated from Yale University in 2005 with a bachelor's degree in political science. Studied at Yale University (BA, political science, 2005) Studied at East Brunswick High School (2000)
- Boards
- Serves on the board of Reddit. Serves on the board of Dropbox. Serves on the board of Kalshi.
- Communities
- Seibel was an early mentor to Airbnb's co-founders and recommended them to Y Combinator in 2008. Seibel advocates for diversity, access to capital, and mentorship in tech, speaking at conferences including TechCrunch Disrupt, AfroTech, and Startup Grind. At Yale, Seibel was active in the Black Student Alliance.
- Hobbies
- Spends much of his free time cooking, reading, traveling, and going for long drives. Runs CooksLarder.com featuring his favorite cooking ingredients and recipes. Runs JonathansApps.com featuring his favorite iOS apps for kids.
- Family
- Lives in San Francisco with his wife Sarah, son Jonathan, and daughter Jessica.
- More
- Co-produced the startup podcast 'Dalton + Michael' with Dalton Caldwell. Created the 'Life, Work, and Startups' podcast series of shorts with his brother Jason Seibel in 2021. Has lived and worked in the Bay Area since 2006. Seibel became Y Combinator's first African-American partner in October 2014. Seibel was named Reddit's first Black board member in June 2020, replacing Alexis Ohanian.
Mentioned above: the Y Combinator mafia → · the Yale University mafia → · the Kalshi mafia →
From Michael's own website — common ground for a warm intro.
Board director at KalshiYC W19
Intro paths
Michael went through Y Combinator (Winter 2019) — any YC alum in your network can reach them through the YC community.
In turn, Michael can intro founders to Kalshi's investors below.
Kalshi's investors · 34
Co-founders at Kalshi
Experience
- Y CombinatorPartner Emerituscurrent2025 — present
- Y CombinatorPartner2014 — 2025
- Y CombinatorPart-time Partner2013 — 2014San Francisco
- SocialcamCEO2011 — 2014San Francisco, CA
- Justin.tvCEO2006 — 2011
- Mfume for US Senate 2006Finance Director2005 — 2006
Skills & more
+12 more
E-commerceOnline MarketingDigital StrategyWeb AnalyticsStrategic PartnershipsNew MediaWordPressSEOWeb DevelopmentMobile ApplicationsMobile DevicesCSSFrom Michael's professional profile.
Investments
Investor
AgentnoonBellabeatBishop FoxBotcoBrexCaptain 401kClipboard HealthConcourseCruiseDriposEasyPostEquipment ShareFigmaGive CampusLuggMattermostMotionNashPanorama EducationPayFazzPaystackPine Park HealthPlayers LoungePromiseReach LabsReadyRetell AIRipplingScentbirdSimple AISoftmaxSquireSuperorderVitable HealthVoriWaveyhangry
Per the investor's own website.
Podcasts & interviews
featuring Michael SeibelY Combinator ex CEO Michael Seibel – What Makes the Top 10% f Founders Different?
Finance & Tech Career Advice
Signs Your Company Is Recovering From ZIRP
Dalton and Michael
How To Live In The Social Media Matrix
Dalton and Michaeel
How To Influence Decision Makers
Dalton and Michael
Co-Founder Equity Mistakes to Avoid
Startup School
The Problem With Startup "Experts"
Dalton and Michael
6 more appearances
- Tarpit Ideas: The Sequel2024-07-19
- Y Combinator’s Michael Seibel: How African Founders Can Build Global Tech Companies2024-06-20
- What Is ZIRP And How Did It Poison Startups?2024-06-20
- How New Technology Creates New Businesses2024-05-24
- When Should You Trust Your Gut?2024-04-17
- Why Founders Shouldn't Think Like Investors2024-03-21
Writing
All posts ↗Michael Seibel writes about startup and founder lessons drawn from his time building Justin.tv, Socialcam, and Twitch and from his work at Y Combinator, covering how non-technical CEOs should handle product disagreements, how YC has evolved since 2007, and how founders should manage runway and fundraising without product market fit.
An essay comparing three tech career paths—founder, executive, and employee—outlining the pros, cons, and strategies for each.
An essay outlining product development cycle fundamentals to help startups rapidly iterate, measure, test, and improve products while engaging their teams.
An essay advising college students on decisions—like learning to code and controlling expenses—that shape their future ability to start startups.
An essay advising startup founders to approach public relations like business development, building genuine reporter relationships and generating timely news to earn press coverage.
Seibel recounts a two-hour pre-launch argument at Justin.tv over displaying AM/PM in chat timestamps, teaching him that non-technical founders should avoid turning trivial product decisions into productivity-killing debates.
Seibel compares Y Combinator in 2007 versus today across office hours, alumni networking, fundraising, hiring, demo day size, deal terms, and programs, arguing the current program offers more value.
1 more post
Colleagues at Pi Campus
Frequently asked questions
- Who is Michael Seibel?
- Michael Seibel spent more than 12 years at Y Combinator, serving as CEO of its accelerator and as a group partner who worked with over a thousand startups, before transitioning to partner emeritus in 2025 with an eye toward public-sector work. He co-founded Justin.tv, which became Twitch, and Socialcam, and became one of the most recognizable startup advisors of his generation through YC's videos and office hours.
- Where does Michael Seibel work?
- Michael Seibel is Twitch co-founder and Y Combinator CEO at Pi Campus and Board director at Kalshi.
- What does Michael Seibel invest in?
- Michael Seibel invests in AI & Machine Learning, Deep Tech, Developer Tools, Fintech, Hardware, SaaS.
- What check size does Michael Seibel write?
- Michael Seibel typically writes checks of $150K.
- What boards does Michael Seibel sit on?
- Michael Seibel holds tracked board seats at Dropbox, Kalshi, Reddit.
- What companies has Michael Seibel invested in?
- Investments tracked here include Agentnoon, Bellabeat, Bishop Fox, Botco, Brex, Captain 401k, Clipboard Health, Concourse, Cruise, Dripos, EasyPost, Equipment Share, and 25 more.
- Where did Michael Seibel go to school?
- Michael Seibel studied at Yale University (BA, Political Science).
- What has Michael Seibel written?
- Michael Seibel has 7 tracked posts, including "Three paths in the tech industry: founder, executive, or employee", "Guide to product development", "A letter to college students", and 4 more.
- What podcasts and interviews feature Michael Seibel?
- Tracked appearances include "Y Combinator ex CEO Michael Seibel – What Makes the Top 10% f Founders Different?", "Signs Your Company Is Recovering From ZIRP", "How To Live In The Social Media Matrix", and 9 more.
Paths to reach Michael
People who overlapped with Michael at the same organization — a shared school or employer with one of them is a warm way in.
Together at Y CombinatorMichael: Partner
Founder mafias
Y Combinator mafia8,773
Also came through, then founded or led a company.
+ 8,766 more
Yale University mafia190
Also came through, then founded or led a company.
+ 183 more
Kalshi mafia8
Also came through, then founded or led a company.
+ 1 more
Pi Campus mafia3
Also came through, then founded or led a company.
Same school
Also attended Yale University799
+ 793 more
Shared employers
Also worked at Y Combinator349
+ 343 more