Robert Gibbs, the White House press secretary and close confidante to President Obama, said Wednesday that he was stepping down to become an outside political adviser to the president and his re-election campaign.

Doug Mills/The New York Times

Mr. Gibbs said that he intended to leave in early February. His successor has not yet been decided, he said, but will likely be announced within the next two weeks.

President Obama, who is in the middle of making final decisions on the first major reorganization of his administration, said in a brief telephone interview on Wednesday that Mr. Gibbs would remain a close adviser and “will continue to shape the dialogue politically for many years to come.”

“We’ve been on this ride together since I won my Senate primary in 2004,” Mr. Obama said. “He’s had a six-year stretch now where basically he’s been going 24/7 with relatively modest pay. I think it’s natural for someone like Robert to want to step back for a second to reflect, retool and that, as a consequence, brings about both challenges and opportunities for the White House.”

The departure of Mr. Gibbs is part of a series of moves inside the West Wing as the president prepares for a new phase of his administration. The internal shuffling also could bring a new White House chief of staff, a decision the president is expected to make by week’s end, with an announcement as early as next week.

Mr. Obama has narrowed his choice for chief of staff to Pete Rouse, who is serving in the post on an interim basis, or William Daley, a former commerce secretary and the brother of Chicago’s mayor, Richard Daley. Mr. Daley has signaled to aides that he will accept the position if it is offered by the president, according to an official familiar with the talks. No other candidates are in line for the job.

“You’ll be seeing announcements in due course — obviously, we’ve got a lot of work to do,” Mr. Obama said. “The American people are expecting us to hit the ground running and start working with this new Congress to promote job growth and keep the recovery going.”

He added, “We’re not going to be dilly-dallying along when it comes to making sure that we’re executing on behalf of the American people.”

The president had no public events Wednesday on his schedule, but aides said he was spending at least part of his day lining up a team of advisers who will guide him through the last two years of his term. A priority is reshaping the economic team, with an announcement expected on Friday for a new director of the National Economic Council. Gene Sperling, a counselor to the Treasury who held the position in the Clinton administration, is believed to be the top contender.

The leading potential replacements for press secretary include Jay Carney, a spokesman for Vice President Joseph R. Biden Jr., along with Bill Burton and Josh Earnest, who work as deputies to Mr. Gibbs. Other candidates also could be considered, an administration official said.

“Robert, on the podium, has been extraordinary,” Mr. Obama said, declining to answer questions about who he intends to hire for any position. “Off the podium, he has been one of my closet advisers. He is going to continue to have my ear for as long as I’m in this job.”

Mr. Gibbs will remain part of the president’s inner circle of political advisers, along with David Axelrod, a senior adviser, and Jim Messina, a deputy chief of staff, who also are leaving the White House to focus on the president’s re-election effort. Mr. Gibbs will defend Mr. Obama on television – and will expand his presence on Twitter and other Internet platforms – as well as beginning to define the field of 2012 Republican presidential candidates.

“Stepping back will take some adjusting,” Mr. Gibbs said in an interview Wednesday morning. “But at the same time, I have a feeling that I will keep myself quite busy, not just with speaking, but continuing to help the president.”

He said he has no intention of establishing a political consulting or lobbying business, but he intends to work from the same downtown Washington office where David Plouffe has spent the last two years. Mr. Plouffe, who was Mr. Obama’s campaign manager, will move to the White House and work as a senior adviser to the president.

Mr. Gibbs, who has worked in political campaigns, on Capitol Hill or at the White House for his entire career, said he also plans to try out the speaking circuit this year. He has no immediate plans to write a book – “there are too many books out there already,” he said – but he will be represented by Robert Barnett, a Washington lawyer who negotiates book deals and speaking engagements for a range of clients that include Mr. Obama, Bill Clinton and Sarah Palin.

Mr. Gibbs, 39, has been a loyal advocate for the president and has often fiercely tangled with reporters during his two-year stint as the White House press secretary. His press briefings were frequently laced with sports metaphors – particularly his beloved Auburn Tigers, even though he was a graduate of North Carolina State – and homespun lines from his native Alabama.

Mr. Gibbs began working for Mr. Obama in April 2004, well before it was clear Mr. Obama would win his race that year for the United States Senate and long before it was known that he had a bright future in national Democratic politics. Mr. Gibbs has been at Mr. Obama’s side ever since, serving as far more of a political adviser than a traditional spokesman.

“This has been an extraordinary journey, an amazing privilege to serve the country and to serve this president. It’s an opportunity, quite frankly, of a lifetime,” Mr. Gibbs said. “But it’s important to take a step back and recharge, ahead of 2012, when we transition to the task of re-electing the president.”