Latortue replaces Yvon Neptune, the prime minister appointed by former president Jean-Bertrand Aristide. Aristide resigned and fled into exile Feb. 29 under pressure from armed rebels and countries including France and the United States.
The interim prime minister -- chosen by a council composed of members of Aristide's Lavalas Party, the political opposition and international community -- will be in charge of setting up early elections for a new government.
Latortue was once a chief negotiator for the United Nations Organization for Industrial Development and briefly served as Haiti's minister of foreign affairs. He moved to South Florida in 1994 and last year became a talk show host on the Haitian Television Network of America.
Boniface Alexandre, the former Haitian Supreme Court chief justice, was sworn in as interim president on Monday.
The steps toward forming the interim government came as Aristide loyalists demanding the return of the exiled leader set up flaming barricades and stoned cars.
U.S. Marines said peacekeeping forces on Wednesday would begin helping Haitian police disarm rebel groups.
The effort to disarm rebels follows the worst violence to hit Haiti since Aristide's departure. On Sunday, suspected Aristide supporters fired into a crowd of thousands rallying in the capital Port-au-Prince in celebration of the former president's departure.
Six people were killed and more than 30 injured. Marines said they killed one of the gunmen.
Marines also shot and killed the driver of a car that sped toward a checkpoint late Monday. A passenger was wounded.
Hijackings and robberies have been common at roadblocks since Haiti's uprising began in early February. Motorists often speed through checkpoints to avoid attacks by pro-Aristide militants and rebels, the Associated Press reported.
The Pentagon said Marines were acting within orders in both cases.
"An individual Marine ... has an absolute right to defend himself and those around him," said Marine Gen. Peter Pace, vice chairman of the Joint Chiefs of Staff, according to the AP.