In a post on X, Altman said that he “loved my time at OpenAI.”
“It was a little transformative for me personally and hopefully for the world.”
He promised to “tell more about what happens next later.”
The launch of ChatGPIT sparked a race in AI – seen as the next big chapter in technology – with contenders including tech giants Amazon, Google, Microsoft and Meta.
Microsoft has invested billions of dollars in OpenAI and has incorporated the company’s technology into its offerings, including search engine Bing.
Altman has testified before the US Congress about AI and spoken to heads of state about the technology, as pressure increases for regulation against risks such as AI’s potential use in bioweapons, misinformation and other threats.
Altman will be replaced on an interim basis by Mira Muratti, the company’s chief technology officer, the statement said.
Microsoft has a long-term agreement with OpenAI and is “committed to our partnership and to Mira and the team,” Chief Executive Satya Nadella said in a post.
“Together, we will continue to bring meaningful benefits to this technology to the world.”