David M. Walker, head of the Government Accountability Office since 1998, is resigning to become president of a new $1 billion private research foundation, the GAO said Friday.

Walker, 56, will step down as GAO comptroller general on March 12 to take over as president and chief executive officer of the Peter G. Peterson Foundation.

Peterson, senior chairman of The Blackstone Group and former Commerce Department secretary, has pledged to contribute $1 billion over the next few years to the foundation, which is to focus on such national sustainability issues as entitlement program and health care costs, trade and budget deficits, energy consumption and the education system.

"My new position will provide me with the ability and resources to more aggressively address a range of current and emerging challenges facing our country," said Walker, who was previously a partner with Arthur Andersen LLP and served as Assistant Secretary of Labor for Pension and Welfare Benefit Programs.

The GAO, known as the watchdog of Congress, was founded in 1921 and now has more than 3,000 employees carrying out investigations at the behest of lawmakers and congressional committees. The comptroller general is appointed to a 15-year term by the president from a list of candidates submitted by Congress.

Gene Dodaro, currently the GAO's chief operating officer, will serve as acting comptroller general.