During his college career, Smart's impressive skills in basketball earned him several accolades and achievements. He was regarded as a five-star recruit and was listed as the No. 1 shooting guard and No. 10 player in the nation in 2012.

Smart led the Oklahoma State Cowboys to the NCAA tournament in both 2013 and 2014. During his freshman year, he led the team to a 24-8 record and clinched a No. 5 seed in the Midwest Region. He recorded an impressive performance, averaging 15.4 points, 5.8 rebounds, and 4.2 assists per game, and led the Big 12 in steals, recording 99 and averaging 3.0 per game.

In 2013, Smart was named Big 12 Conference Player of the Year and was also named to the All-Big 12 First Team. He was also named to the First-Team All-American in the same year and was a finalist for the Naismith College Player of the Year award in 2014.

Smart returned for his sophomore year and continued to impress on the court. He led the #7 Oklahoma State Cowboys past #11 Memphis, tying an OSU single-game scoring record with 39 points in November 2013. However, he found himself in a difficult situation when he shoved a fan in the stands during a game at Texas Tech in February 2014. Smart received a technical foul after a verbal altercation with the fan, and he was later suspended for three games.

Despite the incident, Smart continued to excel in his college career and was named one of the 30 finalists for the Naismith College Player of the Year award that year. In his final game for the Cowboys, Smart finished with 23 points, 13 rebounds, 7 assists, and 6 steals. He became the first player in NCAA Tournament history to record 20 points, 10 rebounds, 5 assists, and 5 steals in a game.

Smart decided to forgo his final two years of college eligibility and declared for the NBA draft on April 7, 2014. On June 26, 2014, the Boston Celtics drafted Smart with the sixth overall pick in the 2014 NBA draft.

In summary, Marcus Smart played college basketball for the Oklahoma State Cowboys at Oklahoma State University, where he led the team to the NCAA Tournament in both 2013 and 2014. He was regarded as a five-star recruit and went on to win several accolades and achievements during his college career. Smart's college career was marked with impressive performances, and he became the first player in NCAA Tournament history to record 20 points, 10 rebounds, 5 assists, and 5 steals in a game.