Victim Kemanuel Montgomery died of a stab wound to the chest. Police said Montgomery had alleged gang affiliations.
Tactical officers from the South Chicago District located and arrested Winston in the 8000-block of South Manistee, a police press release said.
Police said in July the incident began when a man slapped a family friend of Montgomery with cerebral palsy. Montgomery then confronted Winston, who stabbed Montgomery with a knife.
The Sun-Times Media Wire contributed to this report.