John Podesta will join President Barack Obama’s inner circle as White House counselor for a year. (Eric Jamison/AP)

John D. Podesta, who was chief of staff to President Bill Clinton and is one of the Democratic Party’s most experienced strategists, is joining the White House to help President Obama salvage what has become a difficult second term.

Podesta, who has been an outside adviser to Obama since leading his presidential transition after the 2008 election, will formally join his inner circle as White House counselor for a year, according to sources familiar with the move.

Podesta’s arrival comes at a critical juncture for Obama, as the president tries to regain credibility after the flawed rollout of the insurance marketplaces under his signature health-care law. Obama also has recruited Phil Schiliro, the legislative affairs director during the president’s first term and a veteran congressional operative, to return to the White House and spearhead health-care issues.

News of Podesta’s appointment was first reported by the New York Times on Monday evening. People familiar with the move confirmed that White House chief of staff Denis McDonough helped recruit Podesta and that Podesta’s portfolio would be broad and would include climate-change issues and executive actions, as well as the troubled health-care law.

Podesta is one of the Democratic Party’s most seasoned political and policy operatives. He served as Clinton’s chief of staff during the Monica Lewinsky scandal and impeachment proceedings in his second term. He went on to found the Center for American Progresss (CAP), a leading Democratic public policy organization, where he served as president.

Podesta is an influential voice in the Clinton political orbit, informally advising Hillary Rodham Clinton in the year since she stepped down as secretary of state. In the past few weeks, he was in talks to help lead Priorities USA Action, the super PAC that supported Obama in 2012 and is positing itself to back Clinton if she runs for president in 2016.

This fall, Podesta founded of the Washington Center for Equitable Growth, a group within CAP that will study income-inequality issues. Podesta was slated to serve as chairman of the group.

Podesta’s appointment comes as some senior aides prepare to depart the White House. Senior adviser Pete Rouse, Obama’s counselor since he joined the Senate in 2005, is exiting, a person familiar with the move said. Podesta, like Rouse and McDonough, is a former top aide to then-Senate Democratic leader Thomas A. Daschle (S.D.), who has functioned as an outside adviser to Obama.