Anthony Heredia, 19 at the time, shot and killed Tiera Franklin in Little Village on July 1, 2022, Chicago police and prosecutors said.
A jury this week found Heredia guilty of killing the teenage girl in Little Village.
Heredia may be sentenced at his next court date at the end of the month.
In 2022, ABC7 spoke with family and friends of the victim who gathered to remember the life of the teen.
Franklin had just buried her mother and her father was killed when she was only 5 years old.
WATCH: Family heartbroken after Chicago high school student killed in Little Village shooting
Family heartbroken after Chicago high school student killed in Little Village shooting
"They tell you they're going out to the store, you expect them to come back home, so it's tragic," Franklin's aunt Juanita Flowers said at the time. "I feel like if I would've been here, maybe an hour, 45 minutes earlier, she would've been in the car with me. She wouldn't have been at the location where it happened."
Police said the girl was shot in her torso near a fast food parking lot in the 2500-block of South Kolin in the city's Little Village neighborhood.
Loved ones said she was with other family members when she was shot. They rushed her to the hospital, where she passed away.
"I was at home waiting on them to come back," Larhonda Sanderson, another aunt of the teen, said at the time. "They never came back."
The family said the teen was going into her senior year, with dreams of becoming a lawyer.
"Looking forward to graduating next year from Curie High School, looking forward to prom," Flowers said.
Police said Heredia was on a bicycle when he pulled out a gun and shot her.
"We just lost her mother in April. We're not even nowhere near healed from that," Krystina Ross, a family friend, said at the time.