The crash happened near Westpoint Toll Plaza at mile marker 1 after a Lake County (Indiana) police pursuit, authorities said.
After police attempted to safely stop the vehicle, it crossed over into the eastbound lanes and hit another car head-on, police said.
The car being pursued was stolen from Chicago and driven by a 20-year-old man from Waukegan, police said. He sustained life-threatening injuries in the crash and was taken to a hospital.
The other vehicle involved in the crash was occupied by a family of four who were all treated for injuries at the scene and taken to a hospital for observation.
Chopper 7 was over the crash at 3:30 p.m., and all eastbound lanes appeared to have been closed as police investigated the scene.
No further details about the police pursuit were immediately available. Charges were pending.
The eastbound lanes were reopened on the Indiana Toll Road after 5 p.m.