Former US Treasury secretary Timothy Geithner, a key player in reviving the US economy after the worst recession in decades, is joining private-equity firm Warburg Pincus, according to a statement on Saturday.

The move marks a departure for Geithner, who has spent most of his career in the public sector and was nominated to Treasury by President Barack Obama in 2009.

The former secretary plans to begin at the New York-based firm, known for its hand in company buyouts, in March, a press release by the company said.

According to the statement, Geithner, 52, will serve as president and managing director "on overall firm strategy and management, investing and portfolio management, organizational and funding structure, and investor relations."

The move puts Geithner in a hands-on role unlike many of the figurehead positions major government officials assume after public service.

Geithner is most famous for designing and overseeing two major bailout packages worth more than $1.5 trillion while he lead the Treasury through the financial crisis that began in 2008.

The moves saved major banks and the US auto industry and helped keep unemployment under 10 percent as businesses and local governments across the country laid off millions of workers in the first months of his term.

Geithner, who served one term as secretary and was replaced in January by Jack Lew, was long keen to return to New York, where he had been president of the local Federal Reserve Bank.

Warburg Pincus, created in 1966, manages more than $35 billion in assets among a portfolio of more than 125 companies.

"As private equity evolves and as our investing practices and funding models continue to develop, Tim's record of leadership through economic and market complexity will be of critical importance as we continue to build for the future," said Joseph Landy, co-CEO of Warburg Pincus.