The shooting occurred just before 9 p.m. in the 2100 block of South Keeler Avenue.
"The offender was shot by police following an altercation," said CPD spokesman Anthony Guglielmi in a tweet at 9:33 p.m.
A 20-year-old man was taken to Mount Sinai Hospital in critical condition and a 37-year-old man was taken to the same hospital in stable condition, the Chicago Fire Department said.
Police said the 37-year-old man is the police officer and was not shot.
Police Involved Shooting - 2100 S. KEELER. Offender shot by police following an altercation. PIO responding and details to follow. pic.twitter.com/Lf2xuvg6w0— Anthony Guglielmi (@AJGuglielmi) February 17, 2019