A fire broke out just before 4:30 a.m. in the 1600-block of West Irving Park road on Chicago's North Side.
Investigators say they received reports of heavy smoke in a restaurant.
The fire soon spread to apartments in the building. The firefighter was hospitalized with a leg and shoulder injury but is expected to be OK.
The restaurant was significantly damaged. The cause of the fire is under investigation.
The Piggery restaurant is listed at 1625 W. Irving Park Road, where the fire was reported.