Fidji Simo, OpenAI’s CEO of Applications and the company’s second-highest-ranking executive, is stepping down from her full-time role. She’ll transition to a part-time advisory position.
Simo shared the news in a staff note Thursday, saying her medical leave has proven longer and harder than expected. She first went on leave in April after a relapse of a neuroimmune condition she’s lived with for seven years.
“I have decided to leave my full-time role at OpenAI and transition to being a part-time advisor,” Simo wrote on X. “Three months ago, I had to go on medical leave after a severe exacerbation of a chronic illness. During that time, it became clear that the road to recovery would be much longer and more complex than I had anticipated.”
Sam Altman responded publicly: “I am really sad about this and very grateful for all fidji has done for openai, and even grateful for her friendship and who she is as a person. we all wish her the best for a speedy recovery. this sucks.”
Who Fidji Simo Was at OpenAI
Simo joined OpenAI’s board in 2024 and took the full-time role of CEO of Applications in May 2025, a newly created position reporting directly to Altman. It was a significant consolidation move. COO Brad Lightcap, CFO Sarah Friar, and CPO Kevin Weil all started reporting to her, freeing Altman to focus on research, compute, and safety.
Before OpenAI, Simo was CEO of Instacart, where she led the company through its 2023 IPO. Before that, she spent over a decade at Meta, including running the Facebook app.
She came to OpenAI with a mandate to grow the consumer business and bring operational discipline. That mandate produced some of the company’s most consequential product decisions of the past year, including the App Directory inside ChatGPT that turned the chatbot into a platform for third-party apps.
The Side Quests Era
Simo’s most visible impact was the “cut side quests” directive she gave the team earlier this year. The message was blunt: stop building standalone products that don’t feed the ChatGPT flywheel.
The first casualty was Sora, OpenAI’s video generation tool, which was shut down in March. The latest is Atlas, the AI-powered browser OpenAI launched last October, which is being sunset on August 9.
Both products are being folded into ChatGPT rather than maintained separately. That was Simo’s thesis: every feature should compound the value of the subscription, not fragment it across products with separate retention curves.
That thesis outlasts her tenure in the role. The question is whether anyone else at OpenAI will enforce it with the same authority.
An Executive Team That’s Getting Thin
Simo’s departure is the latest in a string of executive exits. CPO Kevin Weil left in April. CMO Kate Rouch left around the same time to focus on her own cancer recovery. COO Brad Lightcap moved into a “special projects” role in the April reshuffle.
That leaves Altman with a thin bench for a company valued at $852 billion. The executive team includes CFO Sarah Friar, co-founder and president Greg Brockman, and Denise Dresser, who joined as chief revenue officer in December after two years as CEO of Slack.
Dresser is a name worth watching. She’s the most logical candidate to absorb some of Simo’s responsibilities, given her CEO experience at Slack and 14 years at Salesforce before that.
Bad Timing
Fidji Simo’s departure comes at a tricky moment for OpenAI. The company is widely expected to pursue an IPO, and Simo was seen internally as a likely candidate to take on more responsibility once that happened. Her absence creates a leadership vacuum at the exact moment investors will want to see stable management.
It also lands on one of the busiest product announcement days in the company’s recent history. Just hours before Simo’s news, OpenAI launched GPT-5.6 (in Sol, Terra, and Luna variants) and ChatGPT Work, an agent designed for multistep office tasks. Both were positioned as direct shots at Anthropic.
The product momentum is real. The management question is now open.
The Bottom Line
Fidji Simo was brought in to professionalize OpenAI’s operations and did exactly that, sometimes in ways that made the company uncomfortable. Her departure leaves Altman without the operations executive he trusted to run the business side while he focused on the models.
OpenAI will fill the gap. The question is whether the next person will have the same authority to make the hard product calls, or whether the “side quests” creep back one by one.
