Microsoft disclosed a series of management changes on Tuesday that will alter the shape of its business unit responsible for products like the Zune music player, Xbox gaming console and phones.

Most notably, Robbie Bach, the current head of the entertainment and devices group, will retire from Microsoft after 22 years at the company. As a result, Mr. Ballmer will take a more hands-on role in Microsoft’s gadgets and games by having various division heads report directly to him.

Through a statement and discussions with reporters, Microsoft representatives stressed that Mr. Bach would leave the company on good terms. Mr. Bach’s division has notched a number of successes, including the Xbox, but has also delivered some of the company’s greatest disappointments, including lackluster phone software and the slow-selling Zune. It also misread the burgeoning tablet computer market.

Microsoft recently scrapped a project code-named Courier that included a new type of tablet computer that would have competed against Apple’s iPad.
"For the past 22 years, Robbie has personified creativity, innovation and drive,” Mr. Ballmer said in a statement. “With this spirit, he has led a division passionately devoted to making Microsoft successful in interactive entertainment and mobility.”

Mr. Bach will remain at Microsoft until this fall, at which point he plans to spend more time with his family, Microsoft said.

J Allard, the head of design and development in Mr. Bach’s group, will also leave Microsoft after 19 years at the company, although he will continue to advise Mr. Ballmer, the company said.