The victim has been identified as Norris Bennett, according to the San Francisco medical examiner's office.
Williams said police responded to the area of Griffith Street and Navy Road about 4:40 p.m. Friday after receiving a report that shots had been fired.
He said responding officers found Bennett suffering from a gunshot wound.
Paramedics responded and Bennett was pronounced dead at the scene, according to Williams.
There is no information about suspects at this time, he said.
Williams said anyone with information about the incident should call the San Francisco Police Department's anonymous tip line at (415) 575-4444.