Sam Altman will return as CEO of OpenAI, the startup tweeted early Wednesday morning. The move follows immense pressure from employees and investors on the board that ousted him less than a week ago.

Former Salesforce co-CEO Bret Taylor and former Treasury Secretary Larry Summers will join OpenAI’s board, the Microsoft-backed startup said, with Taylor holding the chair position. Adam D’Angelo, co-founder and CEO of question-and-answer startup Quora, will remain on the board.

Concurrent with Altman’s return, Helen Toner, Tasha McCauley and co-founder Ilya Sutskever were removed as board members. All had been involved in pushing out Altman, although Sutskever later walked back his support for the coup and remains an OpenAI employee as of Wednesday.

“We are collaborating to figure out the details. Thank you so much for your patience through this,” OpenAI said in the message on X, formerly known as Twitter, posted Wednesday at 1 a.m. ET.

On Monday, hundreds of employees, including Sutskever, signed a letter saying that if the board didn’t resign and bring Altman back, the overwhelming majority of employees would move to work with him at Microsoft.

Satya Nadella, Microsoft’s CEO, said in an X post Monday that Altman and his co-founder Greg Brockman would join Microsoft to form a new AI lab. Preparations for that lab were already underway when the announcement from OpenAI came early Wednesday.

That followed an announcement late Sunday that OpenAI had hired ex-Twitch CEO Emmett Shear as Altman’s interim replacement. Originally, the board had said OpenAI technology chief Mira Murati would assume that role, but she soon joined the parade of employees calling for Altman’s return.

“[W]ith the new board and w satya’s support, i’m looking forward to returning to openai, and building on our strong partnership with msft,” Altman wrote in a post of his own on X.

Nadella applauded changes OpenAI made to its board in an X post.

“We believe this is a first essential step on a path to more stable, well-informed, and effective governance,” Nadella wrote. “Sam, Greg, and I have talked and agreed they have a key role to play along with the OAI leadership team in ensuring OAI continues to thrive and build on its mission. We look forward to building on our strong partnership and delivering the value of this next generation of AI to our customers and partners.”

The rapid reinstatement of Altman began to look like a possibility on Saturday as news surfaced that a group of prominent investors, including Microsoft, Tiger Global, Thrive Capital and Sequoia Capital were working to reverse the board’s decision from a day earlier. None of those firms had board seats, and they were caught unaware by the decision.

“OpenAI has the potential to be one of the most consequential companies in the history of computing. Sam and Greg possess a profound commitment to the company’s integrity, and an unmatched ability to inspire and lead. We are excited for them to rejoin the company they founded and helped build into what it is today,” Thrive said in a statement Wednesday.

In a post on X late Saturday night, Altman wrote, “i love the openai team so much.” Brockman, who quit the company after the board removed him as chairman alongside the ouster of Altman, reposted the comment with a heart symbol. Other OpenAI employees did the same.

OpenAI, which was reportedly in talks as recently as last month to sell employee shares to investors at an $86 billion valuation, emerged as the hottest startup on the planet after releasing its ChatGPT chatbot in late 2022. ChatGPT allows users to input simple text queries and retrieve smart and creative answers that can lead to more in-depth conversations.

Altman had been leading the company since 2019 and was serving as both the top executive of a high-flying company and the public face of artificial intelligence research and product development.

Unlike most Silicon Valley startups, OpenAI wasn’t structured like a typical corporation with large chunks of equity controlled by the founders. Rather, it was part of a nonprofit that was started in 2015. The board oversees the nonprofit, which “acts as the overall governing body for all OpenAI activities,” according to Friday’s blog post.

Sutskever and Brockman were both part of OpenAI’s founding team. Original investors included Altman, LinkedIn co-founder Reid Hoffman and Tesla CEO Elon Musk, who reportedly committed $1 billion to the project.

“Returning to OpenAI & getting back to coding tonight,” Brockman wrote in an early Wednesday X post.

Immediately after OpenAI’s board announced Altman’s firing, prominent Silicon Valley investors and founders loudly voiced their concerns and even compared the move to Apple’s decision 38 years ago to fire Steve Jobs. In 1997, Jobs would return and eventually lead Apple to create the iPhone and become the most valuable company in the U.S.

“What happened at OpenAI today is a Board coup that we have not seen the likes of since 1985 when the then-Apple board pushed out Steve Jobs,” longtime startup investor Ron Conway said in an X post. “It is shocking; it is irresponsible; and it does not do right by Sam & Greg or all the builders in OpenAI.”

Former Google CEO Eric Schmidt called Altman a “hero of mine” who built a company that “changed our collective world forever.” Airbnb CEO Brian Chesky described Altman as “one of the best founders of his generation.” And venture capitalist Vinod Khosla said he is a “once in a generation CEO.”

Nadella, who made an unexpected appearance earlier this month at OpenAI’s developer conference, was reportedly surprised and upset by the announcement. His company has invested billions of dollars in OpenAI and is a close technology partner, hosting hefty GPT workloads on its Azure cloud infrastructure.

“This was the pathway that maximized safety alongside doing right by all stakeholders involved,” Shear said in an early Wednesday X post. “I’m glad to have been a part of the solution.”

WATCH: Madrona’s Matt McIlwain talks Sam Altman’s departure as OpenAI CEO

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