University spokesman John Drees said police used chemical deterrents to disperse the crowd after a fire department arson officer was attacked trying to break up an "incident," The (Louisville) Courier-Journal reported.
The Louisville Cardinals beat the Michigan Wolverines 82-76 to claim the NCAA men's basketball championship Monday night in Atlanta.
"There's no better feeling," Abby Middleton, a University of Louisville senior who watched the game at a restaurant just off campus, told the newspaper. "It's my last year. I always believed in them."
The Courier-Journal said police officers also fired paint balls at crowd members who refused to leave so they could be identified later.
Louisville Metro Police Department representative Carey Klain said officers were "monitoring the situation in all areas" and that larger crowds were showing up in the university area.
Klain said officers made 12 arrests and 270 incident runs as of 2:20 a.m. Tuesday on reports of shots fired, domestic disputes, disorderly conduct, alcohol intoxication and fighting.