Harper attended Whites Creek High School in Whites Creek, Tennessee.[1] Harper went to the AAA State Final Four both his junior and senior years. As a senior, he averaged 15 points and 8 rebounds per game.[2] After his senior year season in 2007, Harper was awarded All-District First Team and All-Region First Team.[3]
In 2009 he averaged 3.4 assists per game (10th in the OVC).[4] He was awarded OVC All-Tournament Team in 2009. In 2010 he averaged 3.2 assists pre game (10th), and 1.4 steals per game (7th).[4]
In 2011 he averaged 15.5 points per game (5th in the OVC), 3.4 assists per game (6th), and 1.5 steals per game (8th), with a .431 field goal percentage (7th).[4] In 2011, he was awarded All-OVC First Team, OVC Tournament MVP, and OVC All-Tournament Team after making a three-point shot with 4.2 seconds left for a 62–61 victory over No. 4 Louisville, which was the first big upset of the 2011 NCAA Tournament. Harper was invited to play in the 2011 NCAA Portsmouth Invitational Tournament.[5]
In September 2013, Harper signed with BC Tsmoki-Minsk of Belarus. In preseason action for Tsmoki-Minsk, Harper scored 17 points in a 94–88 win over Budivelnyk.[11]
In July 2014, he was added to the Denver NuggetsNBA Summer League team's roster.[12] Harper scored 7 points in less than 7 minutes against the NBA D-League Select team.[13] Against the Los Angeles Lakers, Harper's defense was irreplaceable as he played over 28 minutes, scoring 8 points, 4 rebounds, 1 assist, 1 steal, and 1 blocked shot.[14]
On September 2, 2016, Harper signed with Estonian club Kalev/Cramo forthe 2016–17 season.[17]
On March 14, 2017, it was announced that Harper moved to B.C. Zenit Saint Petersburg.[18] He averaged 10.6 points per game. On July 7, 2018, Harper signed with the Turkish team Tofaş.[19]
On January 25, 2019, he signed with Sidigas Avellino of the Italian Lega Basket Serie A (LBA).[20] On July 26, 2019, Harper signed a one-year deal with Spanish club Herbalife Gran Canaria. He re-signed the following season and averaged 12.9 points per game.
On July 29, 2021, Harper signed with Limoges CSP of the LNB Pro A.[21] He averaged 15.7 points per game (8th in the league).[22]