Qualls, 33, starred in the films "Road Trip" and "The New Guy." He also is a cast member of "Memphis Beat" and had a recurring role on TV's "Lost."
UsMagazine.com said he recounted on Twitter his alleged brush with the law early Saturday morning.
"Just got out of the ER. I was beaten by a Vancouver police officer for no reason. I got stitches and was released," he said in his message. "I was not arrested because I was innocent. I was handcuffed and bleeding while the cop kept saying to me, 'You think you're [expletive] better than me?'"
The actor said he witnessed "a dude punch a girl" outside of a cafe, then tried to tell a policeman who arrived on the scene what he saw.
"He said if I didn't get out of there, he'd arrest me. I asked why and he tackled me, busted my face and handcuffed me," Qualls said. "I was beaten, detained and released to an ambulance because I was bleeding and drew a crowd who recognized me."