Marshall was reportedly found dead in his apartment, with no official cause of the death being released.
"He gave us so many big buckets en route to the 2014 NCAA tournament. Our thoughts and prayers go out to the family of Jermaine Marshall," said a statement released by ASU.
Marshall played three seasons at Penn State before transferring to ASU in 2013. Marshall averaged 15 points per game in his lone season with the Sun Devils, helping propel the team to an NCAA tournament berth.
Marshall was instrumental in one of the biggest upsets ASU has had in the past five years. He scored 29 points in a 69-66, double-overtime win over No. 2 Arizona on Feb. 14, 2014.
"He was only a Sun Devil for 1 season but man was incredible on and off the floor," ASU announcer Kyle Dodd said in a post on Twitter.
Marshall played professionally for the Houston Rockets, as well as stops in Italy, Greece, France and the Netherlands, before playing with Nantes Basketball Club in France.