Smart's declaration comes about three months later than expected, as nearly everyone thought the Oklahoma State star would leave college after his freshman season in Stillwater.
"It's safe to say that if, by the grace of God I'm healthy and everything, this will be my last year at Oklahoma State," Smart said, according to Yahoo! Sports. "Nothing will change my mind on that. [Oklahoma State] understands. They didn't figure I was coming back this year. They were just as surprised as everyone else."
Smart, a 6-foot-4 guard, would have been projected as a top-five pick in this past June's draft had he decided to go pro. He was an All-American as a freshman, averaging 15.4 points, 5.8 rebounds and 4.2 assists.
As a result, everyone anticipated Smart forgoing his final three years of college basketball to be a lottery pick. Instead, the Texas native wanted to stick around for one more season of college.
"You can only go to college and be a college athlete once," Smart said. "College is a great experience. This is where you have fun. This is where you find yourself as a young man and grow up into an adult before you enter the real world."
Oklahoma State could be top-10 team heading into the preseason.