An attorney who has served in two Bush administrations has been named the acting chief of the Centers for Medicare and Medicaid Services, federal officials said Monday.

Leslie Norwalk, 40, has served on the senior leadership team at the agency for the past five years, currently as the deputy administrator, the Associated Press reported. She will succeed Mark McClellan, who is stepping down.

"She is a nationally recognized expert on Medicare issues and played a central role in the successful implementation of the prescription drug benefit and other reforms to Medicare and Medicaid," said HHS Secretary Leavitt. "I also tapped her to work with the people of Louisiana in redesigning their health care system in the wake of Hurricane Katrina."

Before working at CMS, Norwalk practiced law in the Washington office of Epstein, Becker and Green. She also served in the administration of former President George H.W. Bush in the White House Office of Presidential Personnel.

Norwalk could oversee CMS for several months, or even years, depending upon when President Bush nominates a permanent replacement for McClellan. She will assume the acting administrator role effective Oct. 15.

One of Norwalk's first tasks will be overseeing the next enrollment period for the Medicare prescription drug benefit, which begins Nov. 15.