OpenAI's Fidji Simo Steps Down to Fight an Incurable Illness

Fidji Simo has spent seven years refusing to let an incurable illness set her pace. She ran some of the biggest jobs in tech while she did it,​​​​​​​ the last as​​​​​​​ OpenAI's CEO of Applications and the closest thing Sam Altman has to a number two, and once turned down a full year of medical leave to keep going.

On Thursday she announced that the illness had worsened, and she is trading the full-time role for a part-time advisory post.

"The truth is that I am only making this decision now because I failed to make it many times before," she wrote on Thursday.

A medical exit handled in the open

Fidji has lived with POTS since her 2019 diagnosis. The condition can trigger fainting, severe dizziness and a racing heart, and it has no cure.

She went on leave in April after what she calls a "severe exacerbation", and three months on has concluded that the "road to recovery would be much longer and more complex than I had anticipated".

Rather than force a clean break, OpenAI is keeping her on as a part-time adviser, an arrangement that retains her counsel while she treats a disabling chronic condition on her own terms.

POTS is thought to affect millions, mostly women, yet it is poorly understood and often invisible to employers. This is part of why a candid disclosure at this altitude has weight.

Who inherits what she built

When Fidji joined in May 2025, OpenAI created the CEO of Applications role expressly for her, folding business and product under one leader so that the COO, CFO and Chief Product Officer all reported in to her, while Sam concentrated on research, compute and safety.

Her responsibilities are now being divided three ways, between President Greg Brockman, CFO Sarah Friar and Chief Strategy Officer Jason Kwon.

That reshuffle arrives at an awkward moment with OpenAI weighing a possible IPO, and Fidji seen as a natural candidate for an even broader remit once it went public.

"I am really sad about this and very grateful for all Fidji has done for OpenAI," Sam writes on X, before signing off, "this sucks." 

OpenAI's senior bench already looks thin for a company of its size, which is why attention has turned to Denise Dresser, the former Slack CEO who joined as Chief Revenue Officer in December and could plausibly take on more.

A brutal moment to lose your operator

Anthropic overtook OpenAI in enterprise adoption for the first time in April, according to some surveys, holding around 34% of business AI spend against OpenAI's 32%, and its Claude Code tool now leads the coding market by more than two to one. 

Fidji had already ordered a sharper focus, telling staff the company "cannot miss this moment because we are distracted by side quests". 

On her watch OpenAI shut its Sora video app and pushed resources into its Codex coding tool, and this week it launched a new GPT-5.6 model family and a ChatGPT Work agent aimed squarely at Anthropic.

The human line under the headlines

For seven years Fidji's answer was to push through, right up until her body refused.

"When I went on leave, many people told me I was courageous for prioritizing my health," she writes in an X post.

The lesson she draws lands on the very trait that built her career:

"Grit and endurance are not the only skills required to have impact over decades. Sometimes the harder thing is to stop, listen and trust that taking care of yourself today makes it possible to contribute for much longer tomorrow."