Vietnamese AI researcher Pham Hy Hieu leaves OpenAI citing burnout

“I have made the difficult decision to leave @OpenAI,” Hieu wrote on social media platform X on Friday (U.S. time), adding that working at OpenAI and previously at Elon Musk’s xAI had been a “once-in-a-lifetime experience.”

“I cannot believe I would say this one day, but I am burnt out,” he wrote.

“All the mental health deteriorating that I used to scoff at is real, miserable, scary, and dangerous.”

Hieu, 34, said he would take a break from frontier AI laboratories and seek treatment in Vietnam while exploring new directions.

He previously worked at xAI, where he was involved in development work on the Grok-3 model, according to posts on his social media accounts.

In February 2025, he described the project as the result of months of research and development and said the work required intensive time commitments from staff.

He wrote that he signed a contract with xAI in July 2024 and was assigned technical tasks before his official start date, including work related to managing power fluctuations in the Colossus supercomputer system.

Hieu graduated with honors in computer science from Stanford University in 2015 and later completed a doctorate in machine learning and computational linguistics at Carnegie Mellon University between 2017 and 2021, according to ZNews.

His career has included roles at Google Brain, the National University of Singapore, and startup Augment Computing.

He officially joined xAI in August 2024 and later moved to OpenAI.

In May 2025, he was invited to participate in a visiting professor program at Vietnam National University-Ho Chi Minh City focusing on AI architecture and hardware.

Hieu did not specify his next professional move in his post, saying only that he hoped to recover before deciding on future plans.