What Emanuel leaves behind is more than a staff job. It is the most demanding and influential position in the White House - save for Obama's. The person who holds it is entrusted to shape the president's thinking, prioritize his time, manage scores of egos and issues and keep the White House focused on its goals.
Stepping into that role will be Pete Rouse, a deeply trusted senior adviser to Obama who has made much of his living as a chief of staff. Obama on Friday is expected to herald Emanuel's service, talk of unfinished business and introduce Rouse as interim White House chief of staff, likely for the rest of the year.
Rouse is considered a leading choice to become the permanent chief of staff. So is Tom Donilon, the deputy national security adviser known as a skilled interagency manager, although he may be a logical replacement for national security adviser James Jones upon his expected departure in the coming months. Another top candidate is Ron Klain, although he might be reluctant to leave his job as Vice President Joe Biden's chief of staff.
Obama's choice will come in the context of a personnel reorganization, two years into a grueling presidency, with some key players already planning to leave the White House grind and others likely seeing changes in their portfolio. The results of the Nov. 2 House and Senate midterm elections will also be a factor.
Sources familiar with Emanuel's plans confirmed them to The Associated Press.
Emanuel's departure has been one of the worst-kept secrets in recent Washington history. But that didn't keep the White House from trying. Sort of.
Amid news reports that Rahm was definitely leaving and Rouse was to replace him, White House press secretary Robert Gibbs would not confirm that, working to avoid getting ahead of the president. But Gibbs said Obama would be making twin personnel announcements on Friday. And in a bizarre exchange with reporters, he described Emanuel's legacy, Rouse's skills and the choice of the grand East Room for the event. He even winked in giving one of his answers.
The transition is likely to unfold in a fitting way. Emanuel will talk. Rouse will probably not.
The two men could not be more different in their personalities and style. Emanuel, 50, is a fast-moving, disciplined and notoriously profane manager - the once and future politician who served as an Illinois congressman and always had a longing for running for mayor of his hometown Chicago.
Rouse, 64, shuns the spotlight but has quietly built up an enormous wealth of trust and relationships in Washington. Those close to him say that he provides what Obama needs - a sharp and strategic mind, a sense of continuity, a knack for troubleshooting and an ability to keep people focused on their tasks. Rouse served for years as chief of staff to then-Senate Democratic leader Tom Daschle and is known on Capitol Hill, but he won't be found schmoozing at political dinners.
The mantra in the West Wing is that no one who works for the president is irreplaceable. And yet that's how they describe Emanuel, a whirling force of ideas and energy with expertise in foreign policy, political campaigns, communications and the legislative process. Obama's aides talk of an unquestioned loss.
The plan within the White House is that some of Emanuel's responsibilities will be shared among other senior officials, not just Rouse. White House officials also say it is a strength that Rouse will bring his own style to his job and that every White House expects change and needs it.
Over the last three decades, White House chiefs of staff have typically served for two to three years.
Obama, after winning a seat to the Senate, recruited Rouse to be his chief of staff there and ultimately made him a top adviser in the White House.
In describing his departure on Friday, Emanuel is expected to offer a glancing reference at most to his run for mayor, not wanting to announce from Washington. His official word on that will come later; he is expected to launch a website with a message to Chicago voters soon.
The move pits Emanuel against a growing field of local politicians vying for the job that will be vacated next spring by Mayor Richard M. Daley, who announced in early September that he will not seek a seventh term. Emanuel's victory in the race is no given, with rivals certain to attack the longtime political operative and former congressman as a brusque outsider who belongs more to Pennsylvania Avenue than Michigan Avenue.
Associated Press writer Don Babwin in Chicago contributed to this report.