President Obama has tapped longtime aide Denis McDonough to become his new White House chief of staff. Obama made the announcement on Friday.

President Obama: “He’s been one of my closest and most trusted advisers on my presidential campaign, on my transition team. He has been an indispensable member of my national security team, as well. Denis has played a key role in every major national security decision in my presidency, from ending the war in Iraq to winding down the war in Afghanistan, from our response to natural disasters around the world like Haiti and the tsunami in Japan to the repeal of ’Don’t Ask, Don’t Tell,’ to countless crises in between, day and night, and that includes many nights.”

McDonough replaces Jack Lew, who has been appointed to take over from Timothy Geithner at the Treasury.