Twenty-year-old Carlos Garcia is charged with one count of first degree murder.
The shooting happened June 2 near Piccolo Middle School in the Humboldt Park neighborhood.
Fifteen-year-old Jeremy Baggett died from a gunshot wound to the neck. He was a tenth grader at Orr Academy High School.
According to The Chicago Tribune, prosecutors said Wednesday that Garcia mistook Baggett for a rival gang member.