The shooting left a second man in serious condition, police said.
The two men arrived at San Francisco General Hospital with gunshot wounds.
Harper succumbed to his injuries at the hospital, and the other man was in serious condition early this morning, according to police.
Police believe the two were shot near the corner of Salinas Avenue and Bayshore Boulevard, near U.S. Highway 101, at about 11:30 p.m.
No further information about the victims or possible suspects was immediately available.