After more than a decade shaping the future of startups at Y Combinator, Michael Seibel is officially transitioning into a partner emeritus role. Seibel, a familiar figure in the startup world, shared the update late Wednesday on X, marking the end of an influential chapter with the renowned accelerator.
Seibel’s journey with Y Combinator began long before his leadership days. As a founder, he went through the program twice—first with Justin.TV, the streaming platform that later evolved into Twitch, and then with the mobile video app Socialcam. His deep ties to the accelerator eventually led him to key leadership roles, including group partner, managing director, and ultimately CEO of Y Combinator’s accelerator program.
In a separate blog post, Y Combinator CEO Garry Tan paid tribute to Seibel’s lasting impact. Tan detailed Seibel’s progression from founder to mentor, underscoring how his leadership helped guide hundreds of startups through the YC ecosystem.
Interestingly, Seibel had already begun stepping back from day-to-day operations. In a blog post last year, he openly shared plans to hand over leadership duties, signaling that the winter batch of startups would be his final cycle in an active role. That transition became official this week.
Twelve years is a lifetime in Silicon Valley, and for Seibel, the change appears to be more than just professional. Some signs of this shift reportedly began in 2022 when Garry Tan took over as President and CEO—a move that caught some within YC by surprise. Many had viewed Seibel as the natural successor, especially since Tan was managing a separate venture fund outside of Y Combinator at the time.
While Seibel hasn’t detailed his next venture, his post on X hints at a return to his first passion: public service. He shared plans to unwind this summer before exploring how he can help government better serve its citizens. “Government was the passion of my youth, and I’m excited to reengage,” he wrote, signaling a potential shift from startups to civic impact.
Seibel also expressed heartfelt gratitude to Y Combinator co-founders Paul Graham and Jessica Livingston, crediting them with “changing my life.” His departure is certainly the end of an era, but his influence on Y Combinator—and countless entrepreneurs who’ve passed through its doors—will remain.
The announcement arrives just ahead of YC’s next chapter. The accelerator’s spring batch of startups is set to begin its journey in April, running through June. As the new class of founders gears up, Seibel’s legacy as a mentor, builder, and leader at Y Combinator will undoubtedly continue to inspire.
