Mustafa Suleyman grew up in subsidized housing in one of London’s roughest areas. His father, a Syrian immigrant, drove a taxi. His mother was a nurse with the National Health Service. When the prestigious Queen Elizabeth’s School

accepted him at the age of 11, the family moved into a safer, leafier neighborhood a few miles north.

There, he met 20-year-old Demis Hassabis, after becoming friends with his younger brother. Demis was a chess prodigy and video game designer whose parents — one a Greek Cypriot, the other a Singaporean — ran a London toy store.

Today, they are two of the most powerful executives in the tech industry’s race to build artificial intelligence. Dr. Hassabis, 47, is the chief executive of Google DeepMind, the tech giant’s central research lab for artificial intelligence. Mr. Suleyman, 39, was recently named chief executive of Microsoft AI, charged with overseeing the company’s push into A.I. consumer products.

Their path from London to the executive suites of Big Tech is one of the most unusual — and personal — stories in an industry full of colorful personalities and cutting rivalries. In 2010, they were two of the three founders of DeepMind, a seminal A.I. research lab that was supposed to prevent the very thing they are now deeply involved in: an escalating race by profit-driven companies to build and deploy A.I.

Their paths diverged after a clash at DeepMind, which Google acquired for $650 million in 2014. When the A.I. race kicked off in late 2022 with the arrival of the ChatGPT online chatbot, Google put Dr. Hassabis in charge of its A.I. research. Mr. Suleyman took a rockier route — founding another A.I. start-up, Inflection AI, that struggled to gain traction before Microsoft unexpectedly hired him and most of his employees.

“We’ve always seen the world differently, but we’ve been aligned in believing that this is going to be the next great transition in technology,” Mr. Suleyman said of his old family friend in an interview. “It is always a friendly and respectful rivalry.”