Dublin police say Hammer was playing loud music while sitting in a car at a Hacienda Crossings Shopping Center. They say the officer approached the Grammy winning musician's car because it had an expired plate, and Hammer became argumentative.
MC Hammer, legally known as Stanley Kirk Burrell, says the officer first asked if he was on parole or probation. He was arrested for resisting an officer.
The head of San Francisco's chapter of the NAACP says he understands Hammer's reaction.
"Sometimes people get sick and tired of being stepped on, spat on, dissed," said Dr. Amos Brown with the NAACP SF branch. "Far too many African Americans are profiled while walking and driving."
On Twitter, MC Hammer insinuated police overreacted, and later called it a teachable moment.
The rapper will appear in court next month.