Steven Sinofsky, the exacting chief of Windows and Windows Live, left the company just weeks after delivering the radical revamp of its flagship software product, Windows 8.
With his departure, Julie Larson-Green, Microsofts corporate vice president of program management for Windows, will be promoted to lead all Windows software and hardware engineering, the company said. She also will be responsible for all product development for the Surface tablet.
Tami Reller will retain her roles as chief financial officer and chief marketing officer for Windows and also assume responsibility for the business of Windows, including leading business and marketing strategy.
Both Larson-Green and Reller will report directly to CEO Steve Ballmer.
All the changes were effective immediately. Sinofskys last day was Monday.
Microsoft gave no reason for his departure but indicated the decision was mutual.
It is impossible to count the blessings I have received over my years at Microsoft, Sinofsky, 47, said in a statement. I am humbled by the professionalism and generosity of everyone I have had the good fortune to work with at this awesome company.
Ballmer said in a statement that he was grateful for the many years of work that Steven has contributed to the company. The products and services we have delivered to the market in the past few months mark the launch of a new era at Microsoft.
Sinofsky, a 23-year Microsoft veteran, was named head of the Windows division in 2009. Before that, he had been senior vice president of the group with two other senior vice presidents, Bill Veghte and Jon DeVaan.
Sinofskys leadership has been credited with being part of the reason for the companys comeback after the bug-prone launch of Windows Vista, and for the well-received launch of Windows 7.
Hes accomplished a lot for Windows, bringing it back from the brink of disaster after Vista, said Rob Helm, an analyst with independent research firm Directions on Microsoft.
Before working on the Windows team, Sinofsky oversaw the development of the Microsoft Office system of programs, servers and services.
He also has made missteps.
Under his leadership, Microsoft did not include a browser choice option for certain PCs sold in the European Union something the company had agreed to do to settle antitrust issues.
Because of that, the EU is considering fining the company, and Sinofsky was dinged for it by Microsofts board of directors.
Hes also been a polarizing figure, clashing with other executives and sometimes company partners.
Sinofskys disruptive way of working is no secret, and you can only get away with it if youre wildly successful, said Michael Silver, an analyst with research firm Gartner.