• by Sarah Mahoney  @mahoney_sarah, August 12, 2010

General Motors Co. chairman and CEO Edward E. Whitacre Jr. is stepping down, and will be replaced as CEO by board member Dan Akerson on Sept. 1.

Both joined the company last summer, as part of the government's efforts to steer the imploding automaker back to profitability.

"It was my public duty to help return this company to greatness, and I didn't want to stay a day beyond then," Whitacre said, making the announcement on an earnings conference call to investors and media and posting the company's second consecutive quarterly profit. "We restored profitability, and things look good. There's a foundation in place, and it's a good foundation. I see no reason to delay."

The announcement followed the news that the company posted a $1.3 billion profit for the second quarter, compared to the dizzying $13 billion loss in the same period last year.

"I am very comfortable with my timing," he says, "and I am also comfortable with the decision to make Dan the new CEO. He brings broad business experience. The transition will be smooth, and he will build on the positive momentum GM is building."

Akerson, a managing director at the Carlyle Group, has been CEO of XO Communications and Nextel Communications, and was chairman and CEO of General Instrument Corp.

In the call, GM reported that revenues gained to $33.17 billion, from $23.05 billion in the previous year. "I am pleased with our progress on achieving our business objectives," Chris Liddell, GM's CFO, said, adding that the company delivered strong products, maintained its cost disciplines and progressed on such strategic initiatives as restructuring its European division and acquiring AmeriCredit.

He also says its U.S. market share is stabilizing, focused on Chevrolet, Buick, Cadillac and GMC, its four remaining brands. And the company says it increased its global market share to 11.6%, up from 11.1% in the first quarter.