The crash happened at 4:18 p.m. at 33rd and Huntingdon streets.
Witnesses say a mother was crossing the street with her son at the intersection when the driver of a white Buick Enclave struck the child.
"It sounded like it hit a car, that's how hard the impact was," recalled Carol Green who witnessed the crash. "Everybody was trying to help the little boy and the mother because she was hysterical."
The impact of the crash sent the boy about 25 feet into the air. He was taken by medics to St. Christopher's Hospital for Children where he succumbed to his injuries.
Some witnesses told police the driver appeared to be fleeing gunfire.
"They said that somebody was shooting at him, that's what they said. I don't know the truth to that," said Green.
Police say the striking vehicle, which was stolen from the 26th District, was later found unoccupied on the 4000 block of Balwynne Park Road with three bullet holes in the driver's side window.
Officers are still trying to track down the driver. Anyone with information is asked to call police at 215-686-TIPS.
The child who was killed in the crash has not been identified.