"The last two years have been the best of my life, but it's time to follow my dream and declare for the NBA Draft," Harris said in a statement released by the university.
The 6-foot-4 Harris averaged 16.7 points and four rebounds per game this past season. He's considered one of the top shooting guards available in the June 27 NBA draft and is expected to be taken somewhere in the Top 20 picks, according to several NBA executives.
"Not only do I fully support and celebrate Gary's decision, but after my information gathering process, I recommend it," Spartans coach Tom Izzo said in a statement. "I expect Gary to be a high pick in the draft, but more importantly, I know that he is well prepared for a long career."