Rouse is a relatively quiet operator compared to Emanuel (pictured), who is famous for his colourful language [AFP]

Barack Obama, the US president, has announced the resignation of Rahm Emanuel, his top aide, to pursue a run for Chicago mayor in a prelude to a wider staff shake-up expected at the White House.

Obama on Friday replaced the blunt-spoken Emanuel as White House chief of staff with low-key senior adviser Pete Rouse, sticking with an insider for the time being with November 2 congressional elections looming.

The US president gave a star treatment to Emanuel, who helped shepherd through the Congress Obama's $814 billion stimulus and his overhauls of US healthcare and financial regulations.

Obama used the White House East Room for the ceremony, essentially giving Emanuel huge media attention as he leaves to seek to become mayor of the Midwestern city they both call home.

"He just brings an unmatched level of energy and enthusiasm and commitment to every single thing that he does," Obama said of Emanuel.

Quiet operator

Rouse, 64, is one of Obama's longest-serving aides, working for him since Obama was a US senator from Illinois. He was one of three White House officials with the title Senior Adviser to the President, along with David Axelrod and Valerie Jarrett.

Rouse is a relatively quiet operator compared to Emanuel, who is famous for his colourful language.

"Obviously these two men have slightly different styles," Obama joked. "Pete has never seen a microphone or a TV camera that he likes."

Emanuel, who once sent a dead fish to a pollster who drew his ire, was given the inevitable goodbye gift at the White House senior staff meeting - a dead Asian carp wrapped in newsprint from the Chicago Tribune and Sun-Times.

The prankster who presented it to him was senior economic adviser Austan Goolsbee.

"I know that I pushed you all very hard. But I did it in service to the president and I believe that our whole country is better off for it," Emanuel told them.