McCollum played college basketball at Goshen College from 2006 to 2010. He graduated as the school's all-time leading scorer with 2,789 points.[3] He was named an NAIA DII All-American in all 4 years at Goshen College. He was also named a First Team NAIA Division II All-American in his senior season.[4]
In the summer of 2014, McCollum signed a one-year deal with the Zhejiang Golden Bulls of the Chinese Basketball Association (CBA).[9] On January 30, 2015, he set the new single game scoring record in the Chinese Basketball Association, with 82 points scored in one game. McCollum also added 10 rebounds and 4 assists in the same game, but his team, the Zhejiang Golden Bulls, lost the game to the Guangdong Southern Tigers, by a score of 129–119.[10]
On July 14, 2017, McCollum signed with the Turkish club Anadolu Efes, of the European-wide top-tier level, the EuroLeague, for the 2017–18 season.[17] On November 14, 2017, McCollum recorded 31 points, shooting 8-of-11 from 3-point range, along with four rebounds and three assists in a 92–72 win over Maccabi Tel Aviv. He was subsequently named EuroLeague Round 7 MVP.[18] On June 28, 2018, McCollum and Efes officially parted ways.[citation needed]
Russia
On September 21, 2018, McCollum signed with the Russian team Unics Kazan for the 2018–19 season.[19] He averaged 19.9 points per game in the VTB league. On July 19, 2020, McCollum parted ways with the team.[20]
On September 7, 2020, he signed with Khimki of the VTB United League.[21] McCollum averaged 14.1 points per game in VTB league play.
On August 17, 2021, he signed with Lokomotiv Kuban of the VTB United League.[22]
McCollum has competed with Overseas Elite in The Basketball Tournament (TBT). He was a point guard on the 2015, 2016, 2017 and 2018 teams that all won the championship game of the winner-take-all tournament. In 2017, McCollum averaged 13.7 PPG during the tournament.[24] In TBT 2018, McCollum played six games. He averaged 13.2 PPG, 2.8 assists per game and 2.7 rebounds per game. Overseas Elite reached the championship game and played Eberlein Drive, winning 70–58 for their fourth consecutive TBT title. McCollum was also named to the TBT 2018 All-Tournament Team. McCollum did not play in TBT 2019, due to getting married.[25]