The shooting happened in the parking lot of Crossroads Charter School, near the intersection of North Tryon Street and Old Concord Road, around 10 a.m. The child was taken in emergency traffic to Carolinas Medical Center.
Officers took Oshane Delando Walker, 17, into custody at 1008 Bilmark Avenue, which is in the Hidden Valley neighborhood. Walker used to attend Vance High School.
The teen was arrested last month and charged with breaking and entering a car and attempting to steal a car.
Police said they are still looking for two other people who may have been involved in the shooting.
Crossroads Charter School is a tuition-free publicly-funded facility that primarily teaches high school students at risk of dropping out of school. It is not part of the Charlotte-Mecklenburg Schools system. About 300 students are enrolled.