Michael Watkins, 22, broke into the zoo last November and killed a patas monkey. In March, he pleaded guilty to felony attempted grand theft and cruelty to animals.
Watkins was sentenced to serve at least one year in state prison while undergoing a treatment plan. A judge will then re-visit his sentencing after a year.
"I know my actions were selfish and it impacted Zoo Boise, the public and Boise itself," Watkins said in court Thursday. "I would like to formally apologize to all involved." | Video of Watkins in Court
Watkins had originally been charged with felony burglary and grand theft and was scheduled to go to trial in May.
Prosecutors say Watkins had hoped to steal the animal before he was bitten and clubbed it to death with a tree branch.
A security guard spotted the Watkins, who ran, and the animal died a short time after it was found by zoo officials.