Satya Nadella

Nadella was a 22-year Microsoft insider running the cloud and server business when he succeeded Steve Ballmer in 2014, after a search that considered outsiders. He moved the company from defending Windows to building Azure cloud services, made Office available on rival platforms and changed an internally combative culture. Microsoft's market value rose many times over in the following decade, the clearest evidence on this list that an internal successor can change direction.