The child was unharmed, but video from the scene shows the car seat stained with blood, and a bullet hole in the car's front windshield.
The shooting happened just after 11 a.m. Sunday at Arlington Avenue and Tyler Street in Riverside.
Police say there was another adult in the car at the time of the shooting who took the baby to safety.
The man who was shot was brought to a local hospital and later pronounced dead there.
A suspect has not been identified. The investigation is ongoing.