Eric Brewer entered the plea at his arraignment in San Mateo County Superior Court, Assistant District Attorney Karen Guidotti said.
Brewer is charged with possession of a firearm on a college campus, carrying a loaded firearm in a public place, carrying a concealed loaded firearm, and committing a felony for the commission of a gang, she said.
He faces about three years in prison if convicted.
Brewer was shot in the buttocks at about 1:30 p.m. Sept. 2 in a campus parking lot. He was transported to San Francisco General Hospital and released within the week.
Police believe an altercation between two groups preceded the shooting but have not arrested the alleged shooter.
At his preliminary hearing last month a judge dropped the gang allegation, but the district attorney's office charged him again with being a gang member and committing a felony, Guidotti said.
His pretrial conference is scheduled for Dec. 29, and his trial is set for Feb. 16.
Brewer remains in custody in lieu of $100,000 bail.