President George W Bush has nominated US trade representative Rob Portman as his government's new budget director.
Rob Portman has led US negotiators at the WTO
Mr Portman's move to the Office of Management and Budget sees his deputy, Susan Schwab, replace him as Washington's chief trade negotiator.
The decision will be seen as an attempt to improve the administration's relations with Congress.
A former congressman, Mr Portman will have responsibility for handling the spiralling US federal budget deficit.
President Bush said Mr Portman had shown "an ability to work across the aisle and bring people together to get things done, and he's going to bring that same skill to his new post".
The role of head of the Office of Management and Budget became vacant after the previous incumbent, Josh Bolten, was promoted to White House chief of staff.
The decision to nominate Mr Portman comes at a key stage in World Trade Organisation talks aimed at liberalising international commerce.
But Washington's ambassador to the WTO, Peter Allgeier, said the nomination - which requires confirmation from the US Senate - would not hamper current negotiations.
"There will be no change in US trade policy or in our negotiating objectives as these are the President's objectives and trade policy, not of any individual," he said.