Police said the crash happened in the Greater Grand Crossing neighborhood's 7400-block of South Lafayette Avenue just before 3:40 a.m.
A 25-year-old woman was driving a light-colored SUV southbound when she hit a 19-year-old man, who was on the street, police said.
The man was transported to the University of Chicago Medical Center, where he is listed in critical condition.
Officers took the driver into custody, and charges are pending.
Police did not immediately provide further information.
INTERACTIVE SAFETY TRACKER Track crime and safety in your neighborhood