John Atterberry, 40, died Monday from injuries sustained in the shooting.
He was shot in the face and upper body as he drove past Tyler Brehm in Hollywood Friday.
Investigators said Brehm, 26, walked down the middle of Sunset Boulevard near Vine Street on Friday, firing at motorists with no clear target until two police officers in the area, an off-duty motorcycle officer working movie set security and an LAPD detective, fatally shot him, authorities said.
Minutes beforehand, Atterberry was critically injured by Brehm.
Two other victims in other vehicles sustained less-serious injuries, one from a bullet to the leg, the other from a bullet graze.
Atterberry was a music-industry executive.
Amateur video taken at Friday's shooting scene showed the suspect, Brehm, pacing back and forth near the busy intersection of Sunset Blvd. and Vine St., firing close to 20 rounds from what appeared to be a .40-caliber handgun.