- Fidji Simo joined OpenAI as CEO of Applications in August 2025, reporting directly to Sam Altman.
- She spent four years running Instacart, taking it public on Nasdaq in September 2023 under the ticker CART.
- Before Instacart, she spent a decade at Meta, where she rose to run the core Facebook app used by three billion people.
- She grew up in Sète, a small Mediterranean fishing town in southern France, the daughter of a fisherman.
A 2026 Seat at the Table of the Most Valuable AI Company on Earth
In August 2025, Fidji Simo left her job as CEO of Instacart to become CEO of Applications at OpenAI. The role places her directly under Sam Altman and puts ChatGPT, the API business, and every consumer-facing product at the $500 billion AI company under her watch.
It is, by any measure, one of the most consequential operating jobs in tech. And it went to a woman who, fifteen years earlier, was a recent HEC Paris graduate with no American work visa and no American network.
Her Instacart tenure is what got her the call. Under Simo, Instacart went public in September 2023, survived the collapse of pandemic-era grocery demand, and by early 2026 trades at a market capitalization of roughly $15 billion on $3.4 billion in annual revenue. The advertising business she built from scratch now generates more than $1 billion a year.
But the story starts much earlier than Instacart. It starts on a fishing boat.
A Fisherman’s Daughter From Sète Who Wanted More Than the Mediterranean
Simo was born in Sète, a working-class fishing town wedged between a lagoon and the Mediterranean in the south of France. Her father was a fisherman. Her mother raised the children. Nobody in her family had been to university.
She was the first. She talked her way into HEC Paris, one of Europe’s most selective business schools, and worked night shifts to pay tuition. HEC is the kind of place where most students arrive with a trust fund and a last name. Simo arrived with a scholarship and a Sète accent.
”I grew up in a town where no one had ever left to do something like this. I didn’t know what I didn’t know, and that was a gift.”
She graduated in 2006 and left France for the US the first chance she got.
Ten Years Inside Facebook, From Ad Intern to Running the Blue App
Her first American stop was eBay. Then, in 2011, she joined Facebook. She would stay for a decade.
Simo started on the monetization side, building out ad products at a time when Facebook was still figuring out how to make money on mobile. She was an early architect of video on the platform, launched Facebook Live, and eventually took over the entire Facebook app — the “blue app” used by roughly three billion people every month.
Running the Facebook app meant sitting on Mark Zuckerberg’s management team, owning the product roadmap for the largest social network ever built, and shipping changes that moved quarterly revenue by hundreds of millions of dollars. By 2021, she was one of the most senior women in all of Silicon Valley.
The Call From a Struggling Grocery Unicorn
In August 2021, Instacart’s founder Apoorva Mehta stepped aside and the board began hunting for an outside CEO. They wanted someone who had built consumer products at massive scale. Simo fit.
She took the job having never run a company. Instacart had just been valued at $39 billion in a private round — a number inflated by pandemic panic-buying that everyone on the inside knew was about to unwind. Grocery delivery volumes were already slowing. Competitors were piling in. The IPO window was narrowing.
”Instacart was never going to be Amazon. My job was to figure out what it actually was, and then build that.”
From Delivery Fees to a Real Platform Business
Simo spent her first two years rewiring what Instacart actually sold. Delivery fees alone could not support a public company, so she turned the grocery network into a three-sided platform.
She launched Instacart Ads, letting CPG brands pay to appear in front of shoppers on the app. By 2024 that business was generating roughly $1 billion a year at high margins. She accelerated the rollout of Caper Carts, AI-powered smart shopping carts that now sit inside physical grocery stores from Kroger to Wakefern. And she pushed the Connected Stores program, selling grocers software and hardware to modernize their aisles.
Revenue diversified. Margins improved. Instacart became less of a gig-economy middleman and more of a retail technology company.
September 19, 2023: The IPO That Reset Expectations
Instacart priced its shares at $30 on the night of September 18, 2023. The next morning it opened on the Nasdaq at $42 under the ticker CART, closed the first day at $33, and finished the week at a market capitalization of around $11 billion. That was about a quarter of the 2021 private mark.
It was not a celebration. It was a reckoning — and a rescue. The company was public, liquid, and profitable on an adjusted basis. Over the following two years the stock climbed as the ad business kept compounding and the cost structure tightened. By the start of 2026, Instacart trades near $15 billion, and Wall Street stopped treating it as a pandemic relic.
Simo had been hired to land the plane. She landed it.
The Call From Sam Altman That Changed Everything
In August 2025, Sam Altman called. He wanted someone to own the entire applications layer at OpenAI — ChatGPT, the developer API, the new consumer products coming down the pipe — so that he could focus on research, compute, and the geopolitics of frontier AI.
Simo announced her move in a letter describing OpenAI as “the most important company in the world to work at right now”. She reports directly to Altman and now owns the product roadmap for the tools that hundreds of millions of people use to interact with AI every day. Her Meta years taught her how to run a product used by billions. Her Instacart years taught her how to turn a product into a business. OpenAI needs both.
”This is the most consequential product opportunity of my lifetime. I couldn’t say no.”
The Sète kid who once worked nights to pay her HEC tuition now sits across the table from Altman, deciding what ChatGPT becomes next. The arc from a Mediterranean fishing dock to the applications chair at OpenAI is not a metaphor. It is a résumé.
