A two-time consensus All-American, Carey was the Pac-12 Offensive Player of the Year in 2013 after totaling 1,885 yards, 19 touchdowns and an average of 157.1 yards a game.
Six times he eclipsed 150 yards -- including 206 yards and four touchdowns on 48 carries in a 42-16 win over then-No. 5 Oregon.
"I'm excited for the next phase of my career and to enter the NFL draft," Carey said in a statement. "I want to thank God, my family, Coach [Rich] Rodriguez, Coach [Calvin] Magee and all of my coaches for everything they've done for me. My time playing football for Arizona will always be very special to me and I want to thank the fans and the Tucson community for supporting me throughout my career."
Carey, who missed the season opener because of disciplinary reasons, rushed for at least 100 yards in every other game. He also had 26 receptions for 173 yards and a touchdown.
"Ka'Deem Carey was a great player for us," Rodriguez said. "We wish him all the best as he pursues his professional career."
Carey leaves Arizona as the school's all-time leading rusher, and his 4,232 yards ranks seventh in Pac-12 history.
He either owns or has a piece of 26 school records, including the single-game rushing record (366 yards in 2012 against Colorado) and the single-season rushing record (1,929 yards in 2012).
Dating to last season, Carey rushed for at least 100 yards in 16 consecutive games, the longest active streak in FBS.