The 29-year-old victim was shot once in the chest near 2311 E. Leland Road, close to the Pittsburg Health Center, at about 6:20 p.m., Lt. Ron Raman said.
The victim was transported to John Muir Medical Center in Walnut Creek, where he is in stable condition, Raman said.
Shortly before the shooting, the victim had been involved in a confrontation with at least one person.
"This was definitely not a random act," Raman said.
Police have yet to identify a suspect but have been pursuing leads during the ongoing investigation.
Anyone with information about the shooting is asked to contact police at (925) 646-2441.