Witnesses say they saw Bieber in a black Dodge Ram strike the man, but it appeared to be an accident.
There were many photographers at the scene with cameras flashing as Bieber left a church event at the Saban Theatre.
Video shows Bieber trying to leave the event as photographers surrounded his car and one was hit in the legs as Bieber's truck accelerated.
Bieber remained at the scene and spoke to the man as help was called.