SEATTLE – In a move that surprised many, Microsoft announced late Monday that Steven Sinofsky, the exacting and controversial president of Windows and Windows Live, had left the company just weeks after delivering the radical revamp of its flagship software product, Windows 8.

The announcement came barely two weeks after Microsoft unveiled Windows 8 with launch events in New York City in which Sinofsky, 47, figured prominently.

With his departure, Julie Larson-Green, Microsoft’s corporate vice president of program management for Windows, will be promoted to lead all Windows software and hardware engineering, the company said. She will be responsible for all product development for Windows and Windows Live, in addition to the Surface tablet.

Sinofsky’s 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, a 23-year Microsoft veteran, said in a written 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 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’s leadership has been credited with being part of the reason for the company’s comeback after the bug-prone launch of Windows Vista, and for the well-received launch of Windows 7.

“He’s accomplished a lot for Windows, bringing it back from the brink of disaster after Vista,” said Rob Helm, an analyst with the research firm Directions on Microsoft.