Robert Osborne will head back to Jenner & Block in Chicago as a partner after serving three years as general counsel for General Motors Corp. during the largest U.S. automaker’s descent into and emergence from bankruptcy.

Osborne, 54, will rejoin the firm in September as part of its corporate department, the firm said in a release. GM last week announced that it was naming Michael Milliken, 60, as its new general counsel as of July 20. Milliken has been on the automaker’s legal staff since 1977, the Detroit company said in a release.

At GM, Osborne oversaw a legal staff of about 200 lawyers in 31 countries and was a member of the company’s senior management committee, Jenner said in its release.

Before joining the company in September 2006, Osborne worked for GM as outside counsel stretching back to the mid-1980s, when he was an associate at Kirkland & Ellis, prior to joining Jenner & Block in 2002. Osborne advised the company on its sale of a majority stake in the automaker’s affiliated finance company, General Motors Acceptance Corp., and its Hughes Electronic Corp. unit and the spin-off of Electronics Data Systems Corp.

Shortly after joining GM, Osborne said in an interview with The National Law Journal that the automaker used about 500 different law firms, though about 10 received most of the work, including Jenner and Kirkland.

Prior to leaving Jenner for GM, Osborne had been the chairman of the firm’s corporate department and was on its management and policy committees, the firm said.