As CEO, Nadella joins Bill Gates and Steve Ballmer, the man he replaces, on the board. But Gates is stepping down as chairman. That role will now be taken by John Thompson, Microsoft board member since 2012, who led the team that searched for Ballmer’s replacement and chose Nadella as CEO.

The widely respected Thompson is CEO at Silicon Valley performance measurement company Virtual Instruments. Now 64 years old, Thompson is an ex-IBMer who was often once referred to as John W Thompson, to distinguish him from another John Thompson in IBM’s senior management.  After his 28 years at IBM he became CEO of Symantec until 2009. He is also on the board of Seagate and UPS.

He is one of the most senior African Americans in US business, and was active in President Barack Obama’s 2008 election campaign, when it was rumoured he may have been appointed Commerce Secretary.

Gates moves into the type of role Lee Kuan Yew holds in Singapore, the city state he drove to great success. Gates will remain a board member and be given the extra title of ‘Founder and Technology Advisor’. A Microsoft announcement  said he will “devote more time to the company, supporting Nadella in shaping technology and product direction.”

It is unlikely Gates will ever be able to pull back entirely from the company he founded in 1975, which for many years defined the software industry, and which made him the wealthiest man on Earth. He will be 60 next year, old enough to be a sort of eminence grise, his shadow forever cast across what still remains the world’s largest and most important software company.

With the addition of Nadella, Microsoft’s board of directors now comprises him, Gates and Ballmer, and Thompson along with six other external  directors:

• Dina Dublon, former CFO of JPMorgan Chase
• Maria Klawe, President of Harvey Mudd College
• Stephen Luczo, Chairman and CEO of Seagate Technology
• David Marquardt, General Partner at August Capital
• Charles Noski, former Vice Chairman of Bank of America
• Dr Helmut Panke, former Chairman of BMW.

“Seven of the ten board members are independent of Microsoft, which is consistent with the requirement in the company’s governance guidelines that a substantial majority be independent,” the company said in a statement.