Microsoft Windows and Windows Live Division president Steven Sinofsky, widely tipped to be the next chief executive of the firm, has left with immediate effect.
Sinofsky's departure comes just weeks after the launch of Microsoft's new Windows 8.
The move tightens CEO Steve Ballmer's grip on the company, where he has now replaced the heads of Microsoft's five main divisions over the last four years.
Ballmer said that the firm was grateful for the many years of work that Steven has contributed. "The products and services we have delivered to the market in the past few months mark the launch of a new era at Microsoft," he said in a statement.
"We've built an incredible foundation with new releases of Microsoft Office, Windows 8, Windows Phone 8, Microsoft Surface,Windows Server 2012 and 'Halo 4,' and great integration of services such as Bing, Skype and Xbox across all our products," he added. "To continue this success it is imperative that we continue to drive alignment across all Microsoft teams, and have more integrated and rapid development cycles for our offerings."
Following Sinofsky's departure, Julie Larson-Green will be responsible for all Windows software and hardware engineering, while Tami Reller retains her roles as chief financial officer and chief marketing officer, while also now being responsible for the business of Windows.
Sinofsky said: "It is impossible to count the blessings I have received over my years at Microsoft. I am humbled by the professionalism and generosity of everyone I have had the good fortune to work with at this awesome company."
Sinofsky, who joined Microsoft in 1989, took over the responsibilities of Windows Division in July 2009.