Sam Altman turns 40 today (April 22), entering middle age not in quiet retreat but at the peak of global influence. Altman’s career follows a familiar Silicon Valley arc: a gifted young coder, a college dropout and an early startup founder. But it wasn’t until he turned OpenAI from an obscure nonprofit into a $300 billion tech powerhouse that Altman truly became a household name. In the age of ChatGPT, Altman isn’t just building products—he’s shaping the very terms of our future.
We don’t know how Altman is spending the day, though it’s likely a low-key affair. Altman and his husband welcomed a baby just two months ago, which may mean more lullabies than headlines tonight. Still, for someone who’s spent the last few years thinking in decades and lifetimes, 40 is a milestone worth noting.
Here’s a look back at the moments that brought Sam Altman from teenage hacker to one of the most closely watched figures in tech.
2005 to 2014: From startup founder to investor
After dropping out of Stanford in his sophomore year, Sam Altman launched his first company, Loopt, a location-sharing app that let users broadcast their whereabouts to friends. It was among the earliest startups funded by Y Combinator (YC), then a fledgling startup incubator. Altman stayed close to YC after his time in its accelerator program. In 2011, he joined the incubator as a part-time partner.
Loopt struck deals with carriers like Sprint in 2012, but the app failed to gain traction with users. That year, it was acquired by Green Dot Corporation for $43 million. Altman used the moment to pivot into investing, co-founding a venture capital firm called Hydrazine Capital with his brother, Max Altman.
In 2014, YC founders Paul Graham and Jessica Livingston tapped Altman to succeed Graham as president, and Altman accepted. Under his leadership, YC cemented its reputation as the world’s leading startup incubator.
2015 to 2022: The quiet rise of OpenAI
In 2015, Altman co-founded OpenAI with Elon Musk, then a friend and collaborator, now more of a rival. The organization launched with $1 billion in pledged funding from Altman, Musk, Peter Thiel, Amazon Web Services, and others.
Altman and Musk initially served as co-chairs. But in 2018, Musk exited after Altman declined his proposal to take over leadership of the company. His departure—and the loss of his financial backing—left OpenAI in a vulnerable position. In response, the organization created a for-profit subsidiary in 2019 to fund its research, while control remained with the original nonprofit board.
That same year, the new for-profit arm secured a key partnership with Microsoft, which provided cloud services through Azure and began integrating OpenAI’s models into its products. Altman also stepped down as president of Y Combinator to focus on OpenAI full-time. During his five-year tenure, YC helped launch nearly 1,900 companies, including Airbnb, DoorDash, Instacart, Reddit and Twitch.
2022 to present: The ChatGPT era
The release of ChatGPT in November 2022 marked a turning point, catapulting A.I. into mainstream awareness. The chatbot’s ability to generate quick, coherent and often strikingly human responses dazzled users. More than a million people signed up within days, and in the months that followed, ChatGPT became a household name.
The company’s newfound visibility brought heightened scrutiny. In November 2023, OpenAI’s board abruptly fired Altman, citing a lack of candor in his communications. The move sparked immediate backlash: employees threatened to walk out, Microsoft extended Altman a job offer, and board member Ilya Sutskever publicly recanted his support for the ouster. Within five days, the board was reshuffled, and Altman was reinstated as CEO.
Less than a month after the upheaval, Time magazine named Altman its “CEO of the Year,” calling him “one of the most powerful and venerated executives in the world—the public face and leading prophet of a technological revolution.”
Altman’s personal life
In January 2024, Altman married his partner, Oliver Mulherin, an Australian software engineer. Photos of the small, seaside wedding circulated online. The couple first went public with their relationship after appearing together at a White House state dinner in June 2023.
On February 22, 2025, Altman announced on X that he and Mulherin had welcomed their first child. Their son, whose name Altman chose not to share, was born “early” and spent time in the neonatal intensive care unit. “I’ve never felt such love,” Altman wrote on the Musk-owned social media platform.