Barret Zoph departs from OpenAI after a brief five-month tenure.

Barret Zoph, who recently rejoined OpenAI as the head of enterprise AI sales, has left the company just five months after his return. Zoph came back to OpenAI in mid-January following his role as co-founder and CTO of Thinking Machines Lab, a rival AI firm established by former OpenAI CTO Mira Murati. Upon his return, he was tasked with spearheading OpenAI’s enterprise initiatives, a crucial position as the company aimed to concentrate on major revenue sources like enterprise solutions and coding in preparation for its upcoming IPO.

OpenAI has confirmed Zoph’s departure, and he shared a farewell message in the company’s Slack channels. He has not yet responded to requests for further comments.

Zoph initially exited OpenAI in the fall of 2024 to join Thinking Machines Lab but left that position unexpectedly in January 2026 amid allegations of misconduct related to an undisclosed relationship with a colleague. Murati announced on X in January that Thinking Machines Lab had “parted ways” with Zoph and that a new CTO would be appointed.

Tensions between Thinking Machines Lab and OpenAI have been notable. Murati briefly stepped in as CEO of OpenAI during Sam Altman’s ousting in November 2023, and during a recent trial involving OpenAI, she expressed doubts about Altman’s trustworthiness. After Murati’s departure from OpenAI to establish Thinking Machines Lab in September 2024, several OpenAI employees followed her, but three, including Zoph, returned to OpenAI together this past January. At that time, OpenAI’s CEO of Applications, Fidji Simo, expressed her enthusiasm on X about welcoming Zoph, Luke Metz, and Sam Schoenholz back, noting that their return had been planned for several weeks.