The name of the dead man, an Oakland resident, was not released pending notification of relatives.
The names of the three wounded, a 26-year-old woman who is in critical condition, and a 24-year-old man and 18-year-old woman who are in stable condition, were not released.
Police said the two in stable condition are from Oakland but they do not yet know where the 26-year-old woman is from.
The shooting happened about 9:46 p.m. Wednesday in the 3700 block of International Boulevard.
Sgt. Eric Milina said the four were on the sidewalk when a gunman on foot approached them and began shooting at them before fleeing.
He said police still have not determined if the four knew each other and what prompted the shooting or who was an intended target.
Milina said the 24-year-old man has refused to cooperate with police and that the 18-year-old woman said she was just walking by when the shooting started and did not know the other people..
All but the 18-year-old woman were transported by ambulance to a hospital where the 36-year-old man died. The 18-year-old woman got a ride to the hospital from friends.
The killing was Oakland's 16th homicide of the year. Last year at this time there were 10 homicides in the city.
Police and Crime Stoppers of Oakland are offering up to $25,000 in reward money for information leading to the arrest of the gunman.
Anyone with information may call police at 510-238-3821 or Crime Stoppers at 510-777-8572.