The assault occurred around 2:30 a.m. on May 6 at a restaurant in the 5000 block of Almaden Expressway, police said.
During the assault, which was unprovoked, the victim was knocked unconscious. No weapon was used, police said.
The victim was taken to a hospital and later released, according to police.
Investigators have obtained pictures of who they believe is the suspect in the attack and are trying to identify and locate him.
He is described as a Hispanic or black man in his early to mid 20s who is 5 feet 7 inches to 5 feet 9 inches tall and weighs approximately 190 pounds with an athletic build. He had chopped hair or a goatee on the day of the incident, police said.
Investigators are asking anyone with information about the identity or whereabouts of the suspect to contact San Jose police at (408) 277-4161 or (408) 537-1350. The anonymous tip line is (408) 947-7867.