Fidji Simo resigns from her position as the second-in-command at OpenAI.

      Fidji Simo announced her exit from OpenAI’s senior leadership in a manner reminiscent of how individuals often learn difficult news about their health—slowly, then all at once. In a message on Thursday, she conveyed that her three-month medical leave had not gone as anticipated, with recovery expected to be more prolonged and complex than initially thought. Consequently, she will resign from her role as the company’s chief of applications.

      Simo joined OpenAI just over a year ago as the CEO of Applications, overseeing product and business operations while effectively serving as the company’s second-in-command. She had been on leave since April, and that leave has now transitioned into her departure. Although she will no longer serve as a day-to-day executive, she will continue with the company as a part-time adviser.

      The reason for her departure is medical; Simo disclosed that she had suffered a severe worsening of postural orthostatic tachycardia syndrome, a chronic neuroimmune condition she was diagnosed with in 2019 that impacts heart rate, blood flow, and energy levels. While the condition is manageable for many, flare-ups can be debilitating, and hers has been significant enough to render a demanding operational role unfeasible for the time being.

      Her responsibilities will now be divided among three individuals. Greg Brockman, OpenAI’s co-founder and president, had already taken over product strategy during Simo’s leave, consolidating leadership of ChatGPT and Codex under him. The remaining responsibilities of the applications division will be shared by Chief Financial Officer Sarah Friar and Chief Strategy Officer Jason Kwon.

      Simo's recruitment marked a significant move for OpenAI. A former Facebook executive who later led the grocery-delivery service Instacart, she was one of the highest-profile external hires made by OpenAI, tasked with transforming a research organization into a commercially viable company that could effectively develop and sell products. Her role involved overseeing aspects of OpenAI that interact with everyday users and paying customers.

      During her time, she was behind several commercial initiatives, including the acquisition of the talk show TBPN, which she announced internally to staff. The applications division she oversaw is currently advancing OpenAI’s efforts in advertising and enterprise sales.

      Simo’s exit occurs during an unusually tumultuous time at OpenAI’s top level, which has seen a series of high-profile departures, including a notable single-day triple exit that resulted in the loss of a product chief, Sora lead, and an enterprise technology executive. Her departure removes yet another senior figure from just below Sam Altman.

      The timing of her exit is noticeable in another respect: it coincides with OpenAI’s most rapid phase of product releases in some time, from the GPT-5.6 model family to the new ChatGPT Work agent, with much of this effort falling under Brockman’s expanded oversight rather than hers. The organizational structure that emerged during her absence has, in effect, become a permanent fixture.

      OpenAI characterized the transition as collaborative, noting that Simo worked alongside Brockman during this period. There are no signs of conflict, and both the company’s communication and Simo’s own statements align on the key point: this decision was health-related, not due to internal boardroom issues.

      This departure is quieter compared to typical executive exits in the industry, lacking the drama of poaching, rival offers, or pointed farewell memos. Simo has openly discussed a condition that many choose to manage privately, and her narrative feels more personal than corporate. This transparency marks a small deviation from the usual patterns.

      For Simo, this change represents a step back rather than a complete departure. By remaining involved as an adviser, she keeps the door open for a potential return, should her health permit it. For OpenAI, her exit adds another senior position to fill during a period of continual change within the organization.