He woke as usual at 5 a.m., swam a mile at the Y, read papers and was in the office at 7 for the senior staff meeting at 7:30. There was a meeting in the Situation Room about Afghanistan; a leadership meeting; a conversation with the Senate majority leader, Harry Reid, Democrat of Nevada; a meeting with Senator Orrin G. Hatch, Republican of Utah; budget meetings; several conversations with the president.

Mr. Emanuel, in the interview, rejected any notion that he was reinventing himself for his new job. But he is mindful, he said, that he must fit into a culture that was forged over two years on a campaign, “a group that was part of a journey together.”

Mr. Obama had settled on his fellow Chicagoan to be his chief of staff well before he was elected. He was drawn to Mr. Emanuel’s experience in both the White House and Congress and called him “the whole package” of political acumen, policy chops and pragmatism. He is also a skilled compromiser. “He knows there is a time in this business to drop the switchblades and make a deal,” said Representative Adam H. Putnam, Republican of Florida.

Mr. Emanuel initially resisted taking the job. He came around after Mr. Obama insisted, saying these were momentous times and that the awesome tasks he faced required Mr. Emanuel’s help. The president-elect also assured Mr. Emanuel that the position would be the functional equivalent of “a No. 2” or “right-hand man,” according to a person familiar with their exchanges.

After taking the job, Mr. Emanuel spent endless hours reaching out to lawmakers. Mr. Reid gave out Mr. Emanuel’s personal cellphone number, with Mr. Emanuel’s blessing, at a caucus meeting of about 40 Senate Democrats this month. (“He seems to speak to every senator every day,” said Senator Charles E. Schumer, Democrat of New York.)

Mr. Emanuel has been equally solicitous of Republicans in Congress (who also have been given access to Mr. Emanuel’s private contact information). On days he does not swim, he works out, and conducts business, at the House gym: 25 minutes on the bike, 20 minutes on the elliptical, 120 situps, 55 push-ups and many sweaty conversations with his former colleagues. In a recent encounter there, for instance, with Representative Peter Hoekstra, Republican of Michigan, Mr. Emanuel secured his support for Leon E. Panetta to head the Central Intelligence Agency.