And now the question is: can this mild-mannered, articulate engineer best known for leading Bing, software developer products, and Microsoft's cloud change Microsoft's culture?
Yes, at least one of his former employees tells Business Insider.
The big clue happened last summer, when he shocked the world by using a Mac on stage during the company's annual developer conference, BUILD.
But it was more than that. He wanted to show how Microsoft's cloud, Azure, would be a great choice for programmers, even if the apps they built were not aimed at Microsoft's Windows or Windows Phone operating systems.
Given skyrocketing sales of non-Windows devices, it was critical to the success of Microsoft's cloud to win over all sorts of developers, even those writing iPhone apps.
So he made three choices that were considered crazy controversial by Microsoft's standards:
- He held the developers conference in San Francisco, not Seattle.
- He used a Mac to build an iPhone app on stage in front of 6,000 developers. He was demonstrating how Microsoft's cloud, Azure, could be used for iPhone and iPad apps.
- He showed how Google's Chrome browser could be set as the default browser when building a website with Microsoft's tools.
The tech press noticed. Microsoft was hailed as new company that "plays well with others," as ReadWrite's Owen Thomas noted.
Seattle Times' Brier Dudley declared that the demo made "the bitter platform wars that characterized Microsoft's relationship with Silicon Valley during the 1990s and 2000s seem like ancient history."
At Microsoft, jaws dropped.
"He did the demo off a MacBook in Silicon Valley. That seems like a totally normal thing for people to do, but at Microsoft, there's no way you could think about doing that," Rakesh Malhotra, a 10-year Microsoft veteran, told Business Insider. Malhotra now works at cloud startup Apprenda as a vice president.
"It was a symbolic thing," Malhotra explained.
Nadella was making the point that using another company's technology, even in public, shouldn't matter, and "it got a bunch of headlines because no one at Microsoft had ever done that before."
And that's the attitude needed to turn Microsoft around and bring it safely into the modern post-PC world.