Kevin Weil showed no sign of the heat when he took to the stage at the Marriott Marquis in downtown San Francisco on an unseasonably sweaty early October morning.

Trim and tan, outfitted in the de rigueur Silicon Valley uniform of a slim-fit gray tee, stonewashed blue jeans, and an Apple Watch Ultra, the chief product officer of OpenAI talked easily about the ambitious artificial intelligence-powered future his red-hot employer was building.

"You could imagine a world where you ask it a hard question about how you cure some particular form of cancer, and you let it think for five hours, five days, five months," Weil prophesied in response to a question about the "reasoning capabilities" of AI.

But neither he nor his onstage interlocutor, Anyscale cofounder Robert Nishihara, ever acknowledged the elephant in the room: Weil wasn't supposed to be there.

The event, the AI infrastructure conference Ray Summit, had originally booked OpenAI's chief technology officer, Mira Murati, to speak. Just days before, the high-profile executive had abruptly quit, prompting the last-minute swap. Murati's exit added to a long list of recent departures from OpenAI, one of the world's most valuable and hyped startups, even as it closed a historic $6.6 billion funding round on the day Weil spoke.

If Sam Altman is the starry-eyed visionary of OpenAI, Weil is its executor. He leads a product team that turns blue-sky research into products and services it can sell, putting him at the center of a philosophical rift that has caused spectacular upheaval at the company, which was recently valued at $157 billion.

In two years, OpenAI went from a nonprofit lab nominally working to develop digital intelligence for the public good to a world-famous startup that puts out shiny new products and models every few months. The company is now attempting to become a for-profit operation to lure would-be backers to write bigger checks, which it needs to scale its business. Altman recently announced that the company's flagship product, ChatGPT, now has 300 million weekly users, triple the number it had a year ago.

Along with this astronomical growth, OpenAI has succumbed to a brain drain: Its chief research officer, head of AGI readiness, co-lead of its video-generation model Sora, and the list goes on. While this has sparked alarm bells in some corners of the tech industry, it has also elevated the profile of the senior leaders who have remained. That includes Weil, a relative OpenAI newcomer who joined in June and rapidly became one of its most notable ambassadors.

At a point when employee voices of dissent were growing louder, 41-year-old Weil arrived as a steady-handed product guru with a Midas touch. He was a longtime Twitter insider who created products that made the social media company money during a revolving door of chief executives.

At Instagram, he helped kneecap Snapchat's growth with competitive product releases such as Stories and live video. (Not everything he touched turned to gold, though. Weil also led Facebook's headlong charge into financial services as a cofounder of Libra, its ill-fated stablecoin.)

Weil declined to be interviewed for this article, which is based on conversations with five former senior colleagues, four of whom spoke on the record, and his past public interviews.

Twitter and Facebook were no strangers to chaos and scandal, but even their most challenging times are rivaled by OpenAI's workplace turmoil. There was a failed coup last year, bitter feuds among some workers, and an ongoing existential arms race to build "digital gods."

Weil's peers are certain he's the man to promote harmony. He's spent the better part of 15 years cranking out products that mostly delighted users and made money. He also has something his new employer desperately needs: The ability to pursue the company's best interests and balance human emotions at the same time.

Kevin Weil isn't a household name. But for those in the know in Silicon Valley, he's something better: "He's the get-shit-done guy," said James Everingham, who worked with Weil at Instagram and Facebook.

Sarah Friar, OpenAI's new head of finance, has long admired Weil's product chops. Former Twitter boss Adam Bain called Weil "Twitter's secret weapon" for driving ad revenue. Everingham also described Weil as a workhorse who never shrank from a deadline.

"He brings that stamina, that dogged focus on the outcome," said April Underwood, a venture capitalist who worked closely with Weil on Twitter's ad products.

Weil's relentless work ethic and people skills are recurring themes among former colleagues. At Facebook, two colleagues said he would often badge into the office first and fire off messages late into the night.

One colleague from Planet, a satellite imagery company where Weil worked as president until May of 2024, recalled how he started each week by posting in Slack the top three things on his mind. According to Everingham, Weil's a rare breed of product manager who codes almost as well as he writes memos. That endeared Weil to the engineers he needed to build products.

Weil shrugs off the pressures of work with long runs and Diet Mountain Dew. Every birthday, he runs his age in miles and, in June, marked his 41st year with a 41-mile jaunt near his home in the posh California suburb of Portola Valley, according to a public Instagram post. Weil lives with his venture capitalist wife, Elizabeth, and three children.

"He is a little bit superhuman in just the sheer amount that he works and works out," said Ashley Johnson, chief financial officer and now president of Planet.

Weil set aside a Stanford doctorate in theoretical particle physics to cave out a path in tech, according to a 2017 speech he gave at his alma mater. In 2009, Weil landed at Twitter as a data scientist. At the time, Twitter had little revenue, never mind profit, to show for its many millions of users. That left investors wondering how Twitter would translate its popularity into money.

When Twitter began developing ads a year later, Weil stepped up to lead it. Katie Jacobs Stanton, a venture capitalist who overlapped with Weil at Twitter, said employees debated how to show ads in a way that didn't degrade the user experience, pitting engineers against marketers. Weil threaded the needle. Under his oversight, Twitter launched ads that looked like tweets inside the feed. AdAge reported in 2011 that hundreds of brands had embraced the format, helping to establish the cash flow that made Twitter's IPO possible in 2013.

Then, in early 2016, Instagram cofounder Kevin Systrom asked Weil to dinner as Snapchat was nipping at the Facebook-owned photo app's heels.

Instagram needed to get users, especially teens, to post more; Systrom wanted a pinch-hitter to get new features designed and added to the app and into the hands of Instagram users. Weil told CNBC in 2017 that he had already resigned from Twitter with plans to train for a 50-mile ultramarathon snaking the American River in California's Central Valley. He took the Instagram job and, a month later, finished fifth in the race.

The product leader wasted no time in the photo-sharing battle. In just a few months, Instagram rolled out a feature similar to Snapchat's disappearing photos and videos, then added popular face filters and also introduced a feed-ranking algorithm to highlight more relevant content. According to Instagram, its user base doubled within two years of Weil's arrival, reaching 1 billion monthly users by 2018; Snapchat's earnings statements during the same period indicated that its user growth had flatlined.

Everingham, his former colleague, recounted how Weil identified Stories as Instagram's killer feature and assembled a nimble team of engineers under the CEO's supervision to build it.

"He had this clarity of thinking I haven't seen in anyone else," said Everingham, now an engineering leader of developer infrastructure at Meta.

Weil's tenure at Instagram was defined by a controversial strategy: borrowing liberally from the competition. The features that became Instagram staples had their genesis in a rival's playbook, which neither Systrom nor Weil denied in interviews with Vox and TechCrunch over the years.

This strategy is particularly poignant as Weil steps into his new role at OpenAI, a company navigating a thicket of copyright lawsuits. New outlets, authors, and celebrities have sued OpenAI over using their work to train its large language models.

That's far from the only struggle the product chief faces. He's positioned as one of Altman's top lieutenants at a time when OpenAI's famed brain trust is leaving in droves, often to start competitor companies that may threaten OpenAI's early dominance in the space.

Former OpenAI employees and siblings Dario and Daniela Amodei founded Anthropic, one of OpenAI's most notable competitors, in 2021. Former chief scientist Ilya Sutskever has raised $1 billion for his new venture, Safe Superintelligence. Ex-researcher Aravind Srinivas is working on an AI-powered search engine, Perplexity. In early December, Murati, the former CTO, told Wired she was "figuring out" what her new venture would look like, though it's unclear if her startup will directly compete with OpenAI.

Another threat comes from open-source AI models championed by the likes of Meta. If these free-to-use systems prove good enough for most users, it will make it far harder for OpenAI to effectively monetize its AI models and, ultimately, turn a profit.

Because with over $20 billion funding, according to PitchBook data, and only an estimated $3.7 billion in revenue in 2024 plus losses of $5 billion, according to leaked documents obtained by The New York Times in September), OpenAI still faces a long road to prove that it can deliver a return on the unprecedented volumes of capital plowed into the company. And that's without even getting into the growing concern that improvements in AI models are slowing.

Onstage at the Ray Summit in October, Weil shrugged off the threat of competition. When asked about whether the current gap in quality between open-source models and OpenAI's premium AI products will shrink, he quipped: "I mean, we're certainly going to do our best to make it grow."

In theory, a proven leader like Weil could help guide the operation past the power struggles and talent losses toward a more steady state. By all accounts, he's a deft conciliator who can empathize with the needs and concerns of multiple stakeholders.

"He's somewhat of a diplomat," said Jacobs Stanton, his former Twitter colleague.

At Facebook, where Weil helped develop a stablecoin backed by a basket of international currencies, he had to mediate between crypto natives, the product purists who wanted to take a more user-friendly, less decentralized approach, and policymakers, according to two former Facebook colleagues. The project ultimately couldn't overcome regulatory roadblocks and an exodus of corporate partners; Meta shuttered the project in 2022, selling $182 million worth of assets to Silvergate Bank.

How Weil's experience maps onto his current role remains to be seen. With its several thousand employees, regulators scrutinizing its every move, and 300 million weekly active users of ChatGPT, OpenAI is more complex than any company Weil's stepped into before. In just six months since his arrival, OpenAI has rolled out a large language model that can solve more complex problems via a process the company calls "reasoning," and a search engine within ChatGPT.

Additionally, OpenAI launched a voice mode to talk to ChatGPT, which Weil personally tested as a "universal translator" during recent trips to Seoul and Tokyo. Reflecting on the release, Weil shared on LinkedIn, "It feels normal to me now, but two years ago I wouldn't have believed it was possible."

Last week OpenAI announced an ambitious "12 days of shipmas," a festive product sprint likely to keep Weil working long hours. While he's managed to keep the proverbial plates spinning in his professional life, there's been one noticeable casualty: his workout routine. App data from Strava shows that he's been logging fewer hours of cycling and running each month since he joined OpenAI.

Asked about Weil's exercise, OpenAI spokesperson Niko Felix said Weil recorded 96 minutes of physical activity a day in November. "I would say he's doing quite alright," Felix said.

Melia Russell is a senior correspondent at Business Insider, covering startups and venture capital. Her Signal number is +1 603-913-3085, and her email is [email protected].

Rob Price is a senior correspondent for Business Insider and writes features and investigations about the technology industry. His Signal number is +1 650-636-6268, and his email is [email protected].