Smart was suspended three games Sunday by the Big 12 for shoving a fan in the closing seconds of the Cowboys' loss at Texas Tech on Saturday night.
The conference acted swiftly in banning the All-America guard, saying in a statement the penalty was handed down for "inappropriate conduct with a spectator."
Smart apologized to the fan, his teammates and his family for his role in the altercation before coach Travis Ford expressed support for the sophomore without dismissing the severity of his actions.
"This is not how I conduct myself," said Smart, a top NBA prospect. "This is not how the program is run. This is not how I was raised. I let my emotions get the best of me. It's something I'll have to learn from, a lesson I'll have to learn from. The consequences that are coming with it—I'm taking full responsibility. No fingers pointing—this is all upon me."
Late in Saturday night's game at Lubbock, Texas, Smart tumbled out of bounds behind the basket after trying to block a shot. He was helped to his feet and then shoved Jeff Orr with two hands after it appeared the Red Raiders fan said something to him. Teammates quickly pulled Smart away as he pointed back and shouted in Orr's direction.
Smart will miss games against Texas, Oklahoma and Baylor. He can return for a Feb. 22 home game against Texas Tech. But Ford said Smart will be allowed to practice.
"These guys mean a lot to me, and for me not to be able to be out there with them—it hits me in my heart," Smart said.
Texas Tech released a statement saying it conducted a thorough investigation. Orr denied making a racial slur, and Tech said the evidence backs up Orr's statement.
Orr, who goes to many Texas Tech games every year, has voluntarily agreed to not attend any Red Raiders home or away games for the remainder of the season, according to the statement.
"I would like to take this opportunity to offer my sincere apologies to Marcus Smart, Oklahoma State, Tubby Smith and the Texas Tech Men's Basketball program," Orr said in the statement. "My actions last night were inappropriate and do not reflect myself or Texas Tech—a university I love dearly. I regret calling Mr. Smart a 'piece of crap' but I want to make it known that I did not use a racial slur of any kind."
Big 12 Commissioner Bob Bowlsby, who is at the Winter Olympics in Sochi, Russia, condemned Smart's actions in a statement.
"Mr. Smart's actions were a clear violation of the Big 12 Conference's Sportsmanship and Ethical Conduct Policy," Bowlsby said. "Such behavior has no place in athletics, and will not be tolerated. I appreciate the efforts of Oklahoma State University athletics director Mike Holder in addressing this matter, and believe this is an appropriate response to an inappropriate action."
Ford said Smart already is learning from the incident.
"He understands, and we talked a lot about it, that no matter what is said or anything like that within a context of the game or life in general, whether it's the heat of the moment or no matter what it is, you've got to try to keep your composure as much as you can," Ford said.
Ford said Smart is a good teammate, "no sir, yes sir, do-whatever-you-ask-him-to-do" guy who is positive, even when he struggles.
"I hate it because he gets painted with a certain brush," Ford said. "I understand that. I get that."
Considered one of the best all-around players in the country, Smart has showed frustration more than once during an inconsistent season.
The sophomore guard got off to a fantastic start, leading to speculation that he could be the No. 1 pick in the NBA draft this year. He has struggled in some recent games, though, including a four-point effort against West Virginia when he kicked a chair on the bench. That led to him apologizing to his teammates afterward.
"Marcus puts a lot of pressure on himself at times. It's something we have been addressing for a while," Ford said. "On many occasions he has handled it well, and on a few occasions he hasn't. I never fault his intention to be at his best every time he steps on the court. At times, it may not come across as his best, but Marcus does a pretty good job of analyzing himself and the areas in which he can improve."
Holder said everyone involved in college athletics can learn from the situation.
"Some things are more important than winning and losing," he said. "Your respect you have, your self-image, all that that takes a lifetime to build, can be gone in the blink of an eye. Playing competitive athletics is a privilege. It's not a right, it's a privilege. And that privilege can be taken away from you."
AP Sports Writer Betsy Blaney in Lubbock, Texas, contributed to this report.
Follow Cliff Brunt on Twitter: www.twitter.com/CliffBruntAP