President George W Bush has named John Negroponte as the first US ambassador to Iraq since the overthrow of Saddam Hussein last year.
Negroponte has been described as an outstanding professional
Mr Negroponte, currently the US envoy to the UN, is expected to take over in Baghdad when the US hands power to an interim Iraqi government by 30 June.
The top US official in Iraq, Paul Bremer, is expected to leave once the political transition is completed.
Mr Bush called Mr Negroponte "a man of enormous experience and skill".
The 64-year-old career diplomat had moved on to the corporate world, before the president recruited him to be ambassador to the United Nations.
He led attempts last year to win the Security Council's backing for war against Iraq.
Before that, he helped put together the international security force in Afghanistan after the overthrow of the Taleban government.
If the US Senate confirms him in the post, Mr Negroponte will assume of one of the most politically sensitive jobs in the world today, says the BBC's Adam Brookes in Washington.
It will be his task to run the American efforts on the ground and to turn Iraq into a functioning state.
That is a truly daunting challenge, our correspondent says, given that violence is undermining the reconstruction effort and that the future shape of Iraqi politics is anything but clear.
The United States has taken the lead role in trying to rebuild post-war Iraq, but has also been the focus of violence and severe criticism from Sunni and Shia leaders.