At about 11:20 a.m., police received ShotSpotter alerts indicating multiple gunshots had been fired at Harbour Way and Barrett Avenue, Lt. Bisa French said.
Responding officers found the victim, identified by the Contra Costa County coroner's office as Reginald Preston II, inside a vehicle at Harbour Way and Nevin Avenue.
Preston, who lived in Richmond and Sacramento, was taken to a hospital where he died, French said.
Witnesses reported seeing a black four-door Honda being driven away from the scene, but a description of the suspect or suspects was not available.
A motive for the shooting was still unknown this afternoon, French said.