The shooting took place at about 9:02 p.m. in the 7300-block of South Langley Avenue.
Police officials said an off-duty Broadview police officer shot Jeremiah Myles.
Myles is accused of approaching the off-duty officer with a knife in the Greater Grand Crossing neighborhood, Chicago police said.
RELATED | Off-duty Broadview officer shoots man with knife on South Side, Chicago police say
Police said the 64-year-old off-duty officer was in an alley getting out of his vehicle when he was approached by a man with a knife.
The off-duty officer fired his gun at Myles, hitting him in the legs, police said.
19-year-old Myles was charged with aggravated assault of a peace officer and one felony count for burglary.
The suspect fled but was later taken into custody and transported to the University of Chicago Medical Center, where he was listed in serious condition, police said.
He is due in court on Saturday, Sept. 20.
INTERACTIVE SAFETY TRACKER Track crime and safety in your neighborhood