WASHINGTON -- Steven Rattner, who led the Obama administration's efforts to restructure General Motors and Chrysler through swift, government-led bankruptcies, plans to depart his post, officials said Monday.

Rattner will be replaced by former steelworkers official Ron Bloom, who has been a key member of the task force and adviser to Treasury Secretary Timothy Geithner. The administration said Monday that Rattner had decided to return to private life and his family in New York City.

A leaner General Motors Co. emerged from bankruptcy last week and Chrysler Group LLC shed itself of Chapter 11 protection last month during short stints through the bankruptcy courts once thought impossible. Rattner headed the government's work to reshape the two companies, which were severely threatened by overwhelming debt, poor management decisions and sluggish sales.

"We are extremely grateful to Steve for his efforts in helping strengthen GM and Chrysler, recapitalize GMAC and support the American auto industry," Geithner said in a statement. "I hope that he takes another opportunity to bring his unique skills to government service in the future."

Rattner won praise for his job managing the massive restructuring of General Motors and Chrysler through billions of dollars of taxpayer funds. Appointed to lead the newly created task force in February, Rattner helmed the day-to-day talks that led to concessions at GM and Chrysler. Rattner struck deals with the United Auto Workers union, the car companies' bondholders and Italian automaker Fiat, which aligned with Chrysler as part of the company's reorganization.

When Obama decided he wanted former GM CEO Rick Wagoner to leave the company, it was Rattner who delivered the news to Wagoner.

GM CEO Fritz Henderson, who succeeded Wagoner, said in a statement that Rattner's expertise "was a key contributor toward a new GM emerging in record time."

Rattner's government service came under a cloud with an investigation of an influence peddling scandal back in New York. Authorities have said that Rattner, an investment banker, was unlikely to face charges in the investigation which involved a large state pension fund that provides retirement benefits for more than 1 million government employees.

Bloom will assume leadership of the task force's activities as the government transitions from day-to-day restructuring to "protecting the substantial investment the American taxpayers have made in GM, Chrysler and GMAC," Geithner said. Bloom is a former investment banker who worked with the United Steelworkers union for more than a decade, advising the union through a painful restructuring of the steel industry.

Rattner, a longtime Wall Street financier, was the co-founder of financial firm Quadrangle Group and previously served as deputy chairman and deputy chief executive officer of Lazard Freres & Co. LLC. He is a former reporter with The New York Times and is married to Maureen White, a former national finance chair of the Democratic National Committee.

Rattner had hinted of changes at the task force with GM and Chrysler emerging from bankruptcy. In a conference call with reporters last week, he said "the task force will inevitably get smaller as this becomes more of a monitoring function."

"I would say, speaking for a number of us, including myself, we have been so busy getting to this point that none of us I think, individually, are at a stage that we can tell you what our specific plans are but we should be able to do that in the coming weeks," Rattner said.