Skyler James Smith-Maynard faces a burglary charge for the July 5 heist, authories said. Authorities said a group smashed windows to businesses amid riots that evolved from an earlier demonstration.
Witnesses identified Smith-Maynard as the suspect who entered a business through a broken window and stole a cash register.
He was arrested a short time later.
Portland has seen several nights of civil unrest. Last week, police officials cited the chaotic protests for $23 million in losses to businesses in the downtown area.