The shooting happened along the westbound 91 Freeway near Adams Street around 10:40 p.m. Saturday, according to the California Highway Patrol.
The victim described the suspect's vehicle as a burgundy Honda Accord, saying he saw a muzzle flash from a handgun and heard the gunshots.
A short time later, officers stopped a vehicle fitting that description.
The victim, who was driving a white Chevrolet Silverado, was able to exit the freeway at McKinley Avenue and officers responded.
"A thorough search of the suspect vehicle resulted in locating a loaded Ruger EC9S 9mm handgun, loose ammunition and one used shell casing," said a news release from the CHP.
Two people inside the Honda were taken into custody and the driver, only identified as a Corona man, was later arrested in connection with the shooting.
At least 80 freeway shootings reported since late April, CHP says
The CHP says this shooting appears to be an isolated incident, apparently unrelated to a recent string of BB or pellet gun shootings along Southern California freeways.
The CHP is investigating more than 80 incidents of cars being shot at on freeways, mostly on the 91 Freeway during the morning hours.