In his college debut against Sacramento State, Pullen scored 18 points on 7-of-11 shooting and ended up scoring in double figures in eight of his first 10 games. He was a large part of Kansas State's renewed basketball success. As a freshman, he was one of just three players who appeared in all 33 games. Alongside Michael Beasley, he helped upset #2 Kansas with a season-high 20 points, going 10-for-10 from the free throw line. In the 2008–09 season, Pullen was one of only two players to start all 34 games for the Wildcats. He notched his career best of 38 points against Kansas on Feb. 14, 2011. He recorded at least one steal in 27 games of the 2009 season and had at least one three-pointer in 29 games. In the 2009-10 season, Pullen continued his strong play in his junior season, leading Kansas State to a 29–8 overall record, with wins at Dayton, at UNLV, at Alabama, against Xavier, and against then undefeated, #1-ranked Texas. Playing under coach Frank Martin, Pullen averaged 19.3 points per game on 41.9% shooting. With backcourt mate Denis Clemente, Pullen received accolades for his part in the turnaround in K-State's basketball. In 2009–2010, Pullen and Clemente combined for the third-highest points-per-game of any guard tandem in school history, at almost 35 combined points. They trailed only the combo of Mike Evans and Chuckie Williams in the K-State record books. The two led the Wildcats to the Elite Eight of the NCAA Tournament before eventually losing to Butler. Pullen was selected to the All Big-12 Team that year. As a senior, Pullen and the Cats lost to Wisconsin in the third round of the NCAA tournament and he was named a Fourth Team All-American by Fox Sports. Pullen is the All Time Scoring Leader in the history of Kansas State University Men's Basketball with 2,132 career points.
On September 29, 2016, Pullen signed a one-month deal with Russian club Khimki. On October 31, he re-signed with Khimki for the rest of the season. He was officially released from the Russian team on July 4, 2017.
2017–18 season
On September 22, 2017, Pullen signed with the Philadelphia 76ers. On October 14, his contract was converted to a two-way deal. Under terms of the deal, he split time between the 76ers and their G League affiliate, the Delaware 87ers. On January 4, 2018, he was waived by the 76ers after appearing in three NBA games. On January 7, 2018, Pullen signed with Mahram Tehran of the Iranian Super League for the rest of the season. On February 20, 2018, Pullen signed with Afyon Belediye of the Turkish second-tier Turkish Basketball First League. With Afyon, he won promotion to the first-tier Basketbol Süper Ligi after winning the play-off finals.
2018–19 season
On November 1, 2018, Pullen returned to Cedevita Zagreb for his second stint with the club.
2019–20 season
On July 12, 2019, Pullen signed with Montenegrin club Mornar Bar of the ABA League.
National team career
In August, 2012, Pullen was granted Georgian citizenship, which increased his career options across Europe and allowed him to play for the Georgian national team in EuroBasket 2013. He began playing with the team during EuroBasket qualification in 2012.
