Terrell Webster, 47, of Chicago, was among workers who were caught in the fire.
The fire broke out at the top of the 10-story parking garage where workers believed to be employees of a roofing company were doing work on the elevator penthouse area of The Mart Park Orleans Self Park at 437 North Orleans Street.
Eyewitnesses said they saw workers jumping from the building to escape the flames.
Webster was pronounced dead at the scene. Two workers, ages 50 and 57, were taken to Northwestern Memorial Hospital and two other workers, ages 39 and 51, were taken to Stroger Hospital. All four were in critical condition, according to the Chicago Fire Department.
The victim's son, Terrie Webster, said Webster had four children and three grandchildren and had been a roofer for 20 years. Webster usually worked in Michigan, but took the job at the parking garage Saturday at the last minute.
The cause of the fire was not immediately known. Black smoke could be seen from blocks away.
The Chicago Sun-Times Media Wire contributed to this report.