Washington, Jan 26 (IANS/EFE): US President Barack Obama Friday named Denis McDonough, who had been serving as deputy national security advisor, as his new chief of staff.

"Denis has played a key role in every major national security decision during my presidency," Obama said at a ceremony in the White House's East Room, adding that he is one of his closest friends and advisors.

In the famous May 2011 photograph in the White House's Situation Room that shows Obama monitoring the mission that led to the killing of Osama bin Laden, McDonough, 43, is seated just two chairs away from the president.

Obama said he has been "counting on Denis for nearly a decade, since I first came to Washington, when he helped set up my Senate office", joking that he was among a group of advisors who helped show him everything from "where the restrooms were" to "how you passed a bill".

McDonough is considered well versed in the ins and outs of Congress, having worked for the then-leader of the Democrats in the Senate, South Dakota's Tom Daschle, before joining the staff of then-Sen. Obama in 2007.

"He's the consummate public servant. He plays it straight, and that's the kind of teamwork that I want in the White House," Obama said.

McDonough replaces Jack Lew, whom Obama has nominated to succeed Tim Geithner as treasury secretary.