WASHINGTON — President Obama shuffled up his White House staff Friday, installing a new team largely made up of familiar faces moved to different positions as he gears up for his second term.

Obama named Denis McDonough as his new White House chief of staff. McDonough, 43, has been serving as deputy national security adviser, helping to orchestrate the U.S. military drawdown in Iraq and Afghanistan and the response to the fatal attack on a U.S. diplomatic mission in Benghazi, Libya.

But more than the president’s previous chiefs of staff — Rahm Emanuel, William Daley and Jack Lew — McDonough is an Obama loyalist who has been with him since he was a senator.

Martha Joynt Kumar, a Towson University political-science professor who studies the presidency, said the most effective chiefs of staff have a variety of traits, including those who have experience on Capitol Hill and can balance politics and policy.

Obama called McDonough a “great friend” he has counted on for nearly a decade. “Denis, you’re not just one of my closest friends but you’re also one of my closest advisers, and like everybody here, I cannot imagine the White House without you,” he said.

McDonough’s promotion was greeted by applause from his colleagues in the East Room on Friday, and the president poked fun at his round-the-clock work habits.

“I actually began to think Denis likes pulling all-nighters,” he said.

In 2006, McDonough joined Obama’s Senate staff and later worked on his campaign and transition. When he got to the White House, Obama named McDonough his chief foreign-policy communications strategist, and later to the No. 2 job at the National Security Council.

The chief-of-staff job may not be known by many outside Washington, but it’s one of the most critical in every White House. The chief of staff serves as gatekeeper to the president and helps get his initiatives implemented. Obama plans an aggressive second-term agenda that includes curbing gun violence, overhauling immigration laws and combating global warming.

For years, presidents did not have chiefs of staff. Dwight Eisenhower hired the first after determining that the White House had become too large and unwieldy to manage by himself, said James Pfiffner, a George Mason University professor who has researched chiefs of staff.

Presidents Carter and Ford tried to manage without one, but they found that they could not, he said. “It’s an inside and administrative job, but it’s crucial,” Pfiffner said. “In Washington, it’s one of the powerful positions.”

Other personnel shifts include Rob Nabors, currently the president’s legislative-affairs chief, who will move up to deputy chief of staff; replacing McDonough at the National Security Council will be Tony Blinken, the national-security adviser to Vice President Joe Biden. Dan Pfeiffer, the White House communications director and another early Obama aide, will move up to senior adviser, replacing David Plouffe, who is departing.

Replacing Pfeiffer as communications chief will be his deputy, Jennifer Palmieri.

Serving as deputy senior adviser for communications and strategy will be David Simas, a former White House aide who served as head of polling and focus-group research for the president’s re-election campaign.

Replacing Nabors running the legislative affairs office will be Miguel Rodriguez, a former aide to departing Secretary of State Hillary Rodham Clinton and more recently Senate liaison for the Obama White House.

Lisa Monaco, the assistant attorney general for national security, will move over to the White House to replace John Brennan, the president’s adviser for homeland security and counterterrorism, who has been tapped to take over as director of the CIA if confirmed by the Senate.

The White House announced separately Friday that Christopher Lu, one of Obama’s early aides dating back to his Senate days, will be leaving as White House Cabinet secretary, the liaison to the various government departments. Replacing him will be Danielle Gray, deputy director of the White House National Economic Council. Katy Kale will become the president’s assistant for management and administration, moving up from deputy.

Separately, the first lady’s deputy communications director, Semonti Stephens, said that she was leaving to move to San Francisco.

Material from The New York Times is included in this report.