Microsoft has promoted Steven Sinofsky as the president of its Windows division. Sinofsky, a 20-year Microsoft veteran, recently led the Windows and Windows Live engineering group contributing to the October 22 availability of Windows 7.

As president, Sinofsky assumes the responsibility for the Windows business including both the engineering and marketing functions for Windows, Windows Live and Internet Explorer.

Steve Ballmer, CEO of Microsoft, said: “Steven Sinofsky has demonstrated the ability to lead large teams that deliver great products. The work he and the team have done in getting ready to ship Windows 7 really defines how to develop and ship world-class software. He is a perfect fit to lead the Windows group.”

Sinofsky began his career at Microsoft in 1989 in engineering, and has held multiple positions on Microsoft product teams.

The company added that Tami Reller, currently chief financial officer (CFO) for the Windows division, will take on the additional responsibility for marketing. Reller joined Microsoft in 2001 as part of the acquisition of Great Plains Software. Since joining Microsoft, she has held a variety of positions including corporate vice president of marketing for Microsoft Business Solutions, where she was responsible for the launch of the Microsoft Dynamics brand.

Meanwhile, Jon DeVaan will continue in his role as senior vice president, reporting to Sinofsky.