OpenAI co-founder and chief scientist Ilya Sutskever has decided to leave the Sam Altman-led firm. Ilya Sutskever made the announcement in a post on X (formerly Twitter) on Tuesday.

“After almost a decade, I have made the decision to leave OpenAI. The company’s trajectory has been nothing short of miraculous, and I’m confident that OpenAI will build AGI that is both safe and beneficial under the leadership of @sama, @gdb, @miramurati and now, under the excellent research leadership of @merettm,” Ilya Sutskever wrote.

Ilya Sutskever added that it was an “honour and a privilege” to work with the OpenAI colleagues.

“I will miss everyone dearly. So long, and thanks for everything. I am excited for what comes next — a project that is very personally meaningful to me about which I will share details in due time,” he added.

Following Ilya Sutskever’s announcement, Sam Altman bid him farewell in a post on X, calling the former “one of the greatest minds of our generation, a guiding light and a dear friend”.

“His brilliance and vision are well known; his warmth and compassion are less well known but no less important. OpenAI would not be what it is without him. Although he has something personally meaningful he is going to go work on, I am forever grateful for what he did here and committed to finishing the mission we started together. I am happy that for so long I got to be close to such genuinely remarkable genius, and someone so focused on getting to the best future for humanity,” Altman wrote.

The OpenAI CEO also announced that Jakub Pachocki would replace Sutskever as the firm’s new chief scientist.

“Jakub is also easily one of the greatest minds of our generation; I am thrilled he is taking the baton here. He has run many of our most important projects, and I am very confident he will lead us to make rapid and safe progress towards our mission of ensuring that AGI benefits everyone,” he said.

Sutskever’s departure comes over five months after OpenAI went through a leadership crisis involving the firm’s CEO Sam Altman – who was fired by the company’s board in November last year.

Reportedly, Sutskever had joined in the effort to fire Altman but later signed an employee letter demanding his return. Shortly after Altman returned to the ChatGPT maker company, the board that fired him from his role, including Ilya, was almost entirely replaced after a rebellion by employees.

Who is Ilya Sutskever?

Ilya Sutskever, a Russian-born Israeli-Canadian computer scientist, co-founded OpenAI. He studied at the Open University of Israel between 2000 and 2002, following which he moved to to Canada with his family and attended the University of Toronto.

In 2012, Sutskever built AlexNet in collaboration with Hinton and Alex Krizhevsky. He is also one of the many co-authors of the AlphaGo paper.

Sutskever’s other professional trajectory includes a brief postdoctoral stint with Andrew Ng at Stanford University, followed by a return to the University of Toronto to join DNNResearch, a venture stemming from Hinton’s research group.