Obama told the New York Times in an interview that the impending departure of Pete Rouse, who had worked for him since Obama was an Illinois senator, "will be a tough loss."
"I trust him completely," Obama told the Times. "He is a model of discretion and he has no ego, and he's as wise as they come. So I think it's fair to say that for the remainder of my term in office he will continue to be somebody who I talk to a lot and rely on heavily."
Obama's poll numbers have reached their lowest-ever depths in recent weeks because of a rocky start to enrollment for the health care insurance program in his Affordable Care Act, commonly known as Obamacare.
In recent days, Obama has beefed up his team with two new but familiar faces known for strong ties on Capitol Hill.
Former legislative director Phil Schiliro will return for a short-term appointment to help smooth out the Obamacare mishap.
Schiliro, 57, was a longtime aide to California Democratic Congressman Henry Waxman and also worked for former Democratic Senate leader Tom Daschle.
The White House also recruited John Podesta, 64, for a one-year assignment with a particular focus on climate and energy issues.
Podesta was chief of staff for former Democratic President Bill Clinton and has more recently run the left-leaning think-tank called the Center for American Progress. He also worked for Daschle on Capitol Hill.
Podesta is set to "bring a fresh perspective and a fresh set of eyes to some of the challenges that we've been dealing with here for the last several years," said Josh Earnest, a White House spokesman, in a briefing with reporters on Wednesday.
Earnest told reporters that year-end departures from the White House are "traditional" for staff in high-stress positions and should not be viewed as "a commendation or a condemnation" for their work.
"That is part of a natural transition that you see on an annual basis at the White House, and I would anticipate that you'd see some more of that this year, too," he said.
Rouse, known for shunning the spotlight while skillfully working behind-the-scenes, first worked for Obama as his Senate chief of staff after Obama's election as a senator in 2004.
A graduate of the London School of Economics, Rouse had worked in the Senate since 1971, including 19 years with Daschle.
Rouse and Podesta were part of a team that helped fill Obama's key staff roles when he first took office in 2009.
Rouse became Obama's interim chief of staff after Rahm Emanuel left to run for mayor of Chicago in 2010. When the West Wing ran into difficulties in 2011 under its next chief of staff, Bill Daley, Rouse stepped up to play a bigger role.
Obama told the New York Times that he was not going to let Rouse take leave completely, noting he plans "assignments here and there" for Rouse.
"Certainly I will continue to rely on him for the good counsel and advice that I really can't get from any other people in this town," Obama said.
(Reporting by Roberta Rampton; Editing by Lisa Shumaker)