Gabe Newell dropped out of Harvard in the early 1980s to join Microsoft, where he spent 13 years helping build the first three Windows releases and led the Windows 95 port of Doom. In 1996 he co-founded Valve with Mike Harrington, pouring resources into their first game, Half-Life (1998). Harrington sold his stake in 2000 and Newell steered Valve through a near-bankruptcy fight with Vivendi, then launched Steam in 2003. By 2011 Steam controlled up to 70 percent of the PC digital-game market and became Valve’s main revenue source. Newell publicly criticized console development—calling PS3 work a “waste of everybody’s time”—and praised Linux as “the future of gaming.” Beyond Valve, Forbes estimates he owns at least half of the company and ranks him the richest person in the games industry with roughly $11 billion in 2025. He’s invested in marine research through Inkfish, in neural interfaces via Starfish Neuroscience, and in luxury yacht maker Oceanco. In 2018 he gave $20 million to OpenAI as an informal advisor. He’s also raised charity money with Heart of Racing, supporting children’s hospitals in Seattle and New Zealand, and even launched a Half-Life gnome into space to fund pediatric care.