The president, in a brief telephone interview on Wednesday, said he was eager to put the reorganization into place and make changes after two years on the job. He said he planned to have the personnel realignments finished in the coming days.

“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,” Mr. Obama said. “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.”

As Mr. Obama enters a new phase of his presidency, there are signs that he intends to operate differently. The White House said the president would speak on Feb. 7 to the U.S. Chamber of Commerce, a group that spent millions trying to defeat Democratic candidates and the policies of his administration.

While Mr. Daley and Mr. Sperling are perceived as centrists and could leave liberals further concerned about the administration’s commitment to its views, the real evidence of where the president is heading will not come until the State of the Union address later this month and the unveiling of the president’s budget in February.

The first in a series of staff changes began on Wednesday as Mr. Gibbs, the press secretary, announced that he was stepping down. He said he would leave in early February. His successor has not yet been chosen.

The departures of David Axelrod, a senior adviser to the president, and Jim Messina, a deputy chief of staff, both of whom are moving to Chicago to establish the president’s re-election campaign, have been further impetus to the realignment among political and policy advisers alike. Several of the positions are interwoven, which has created an unusual air of uncertainty for a White House that has enjoyed considerable continuity.