Thamir Ghadhban, the ministry's director of planning before the invasion, will have interim control over Iraq's battered oil sector.
The Pentagon's Office of Reconstruction and Humanitarian Assistance (ORHA) said Mr Ghadhban would have day-to-day control of management, marketing and sales, effectively making him interim oil minister until a new government is formed.
It said Philip Carroll, an American and former CEO of Shell Oil, would separately head an advisory board expected to oversee policy planning for the sector.
"We are committed 100 percent that the Iraqi oil and hydrocarbons wealth is for the Iraqi people," said Mr Ghadhban, a geologist. "I am confident that I'll do all my best with my colleagues to improve the situation."
He has been given the title of chief executive officer of the interim management team, ORHA said in a statement.
"Mr Ghadhban will have day-to-day management responsibility for the sector, as well as sales and marketing functions," it said.
"In the first days following the fall of the Saddam regime, Mr Ghadhban voluntarily stepped into an ad hoc and effective leadership role in the ministry," it said.
Tim Cross, the British deputy to Jay Garner, the retired US general in charge of rebuilding the country, insisted that the people would profit from Iraq's oil, the world's second-largest proven reserves after Saudi Arabia.—AFP