Dušan grew up with Crvena zvezda youth team. He made his professional debut with Zvezda second team Radnički FMP during the 2012–13 season.
His debut with first team of Crvena zvezda was during the 2013–14 ABA League season. He also played two games in Euroleague. However, he decided not to sign professional contract with club.
January 2014 he went to Sunrise Christian Academy in Wichita, Kansas.
On March 8, 2014, Ristić, committed to play basketball for the Arizona Wildcats. On twitter he announced that he will play his senior year for the Wildcats and finish his education.