The boy was struck by a car outside Campbelltown East Public School at 3pm on Monday.
Witnesses say the driver of the car – a red Mitsubishi Mirage – stopped briefly before fleeing the scene.
The boy was taken to Campbelltown Hospital where he is being treated for his injuries, which are not life threatening.
Police are now hunting for the driver of the car, described as being of Caucasian appearance with long brown hair and an olive complexion.
Anyone who witnessed the incident or has information about the driver is urged to call Campbelltown Police Station on 02 4620 1199.