Several people with West Wing experience said that one critical trait a chief of staff needs to bring to their work is the ability to provide the president with solid counsel.
"At the end of the day it's the chief of staff's responsibility to create a comfort zone around the president, a comfort zone where the president can make good decisions and make sure things are getting executed properly," Bartlett said.
Several former West Wing aides said that the White House staff looked to the chief of staff for clues about the president's mood.
Former spokeswoman Dana Perino served in the West Wing during George W. Bush's second term and said that the chief of staff needs to be an anchor for the president's staff.
"A chief helps keep things in perspective, can help you deliver bad news to the boss -- that you feel has your back when you're not in the room," Perino said. "It also is someone that keeps everyone on their toes to avoid mistakes."
Bartlett said one crucial role for the chief of staff that perhaps goes unnoticed outside of the West Wing is managing the president's Cabinet.
"Well you can imagine the collective egos of the people serving in the Cabinet. None of them are ever happy about the role they're playing in policy making, their access to the president," Bartlett said. "The chief of staff decides what type of access the Cabinet gets, where they contribute, how they contribute."
Working Capitol Hill
An equally important part of the job description is the work done at the other end Pennsylvania Avenue – Capitol Hill.
Emanuel came to the White House after serving six years in Congress. Administration officials said that experience was crucial during the push to develop and pass the health care reform bill.
"The White House has its legislative staff but ultimately it can be the chief of staff that cuts the deal with Congress," said Bartlett.
Never a Good Time for Staff Shake-Ups
With the clock always ticking and President Obama's to-do list not getting any shorter, there is perhaps never a good time for significant staff turnover, former White House officials said.
The loss of Emanuel will be felt throughout the Obama White House, especially in the final weeks before the crucial mid-term elections.
"The person who did the strategy and the tactics, the person who coordinated for the administration, working with the leadership in the house and the senate was Rahm," said former Reagan chief of staff Ken Duberstein. "So whether you agree or not that the legislation was helpful, it was part of the president's agenda and on the legislative agenda, Rahm was the driving force."
White House spokesman Gibbs said Emanuel's influence has been felt on every key decision and accomplishment over the last two years.
Emanuel may not be as visible as Gibbs but he still maintained a public presence with Sunday morning talk show interviews and sit-downs with network anchors. Based on his personality and looking at his low-key past, it is unlikely that Rouse will step in and become a fixture on the airwaves.
In fact at the White House event today where the personnel moves were announced, the different styles of the outgoing and incoming chiefs of staff was apparent.
Emanuel is expected to make remarks. Rouse will not.
ABC News' Jake Tapper, Arlette Saenz and Sunlen Miller contributed to this report.