White House economic advisor Larry Summers has announced that he is to leave his job.
His move marks a major staff shake-up for President Barack Obama as he faces growing pressure to revive the sluggish economy.
Mr Summers brought years of experience in economic policymaking to his job as director of the White House National Economic Council.
He is a former Treasury secretary who had grappled with the Mexican peso crisis and other global financial problems in the 1990s.
The president credited Mr Summers with having helped to guide the country 'from the depths of the worst recession since the 1930s to renewed growth.'
However, the outgoing economic advisor had been criticised by some liberal Democrats as being too close to Wall Street.
There were also a number of reports of clashes on the economic team within the White House.
Larry Summers will return to his teaching job at Harvard University by the end of the year.
In a statement released by the White House, he said he was 'looking forward to returning to Harvard to teach and write' about the economy and finance.
While President Obama said he would continue to seek Mr Summers' 'advice and his counsel on an informal basis.'
Mr Summers will be the third high-ranking economic official to depart, leaving Treasury Secretary Timothy Geithner as the sole senior member of that team still in his original job.
White House budget director Peter Orszag stepped down in July and White House Council of Economic Advisors Chairwoman, Christina Romer, left her job at the beginning of this month.
President Obama is seen as highly likely to tap someone from outside the administration to fill Mr Summers' job.
Laura Tyson, a former economic advisor to President Bill Clinton, is among those likely to be considered.
If Mr Obama were to turn to a businessperson, General Electric Chairman Jeffrey Immelt and Richard Parsons, chairman of Citigroup, are among people who have been mentioned as potential candidates.
