The incident began as an attempted traffic stop near Francisco and Polk.
Other police officers pursued and cornered the driver near the Stevenson Expressway and Damen.
The driver struck a police car. Police say as officers were getting the offenders out of their van, shots were fired.
"One officer was struck in the leg and taken to Stroger. The offenders in the vehicle were taken into custody, and they were not injured," police Supt. Jody Weis said.
It's not clear whether the offenders shot the officer or whether it was friendly fire. The officer is expected to recover fully.
Authorities say an investigation into the shooting is under way.