Johnson initially competed at the NCAA Division I level with the James Madison Dukes, but chose to transfer to UMBC after three seasons. He claimed that he was unhappy with his previous school and felt that he would see more immediate success with the Retrievers. One of Johnson's teammates also transferred to the same team with him, making the process smoother in his opinion.[3]
In 2011–2012, Johnson played with the Beltway Bombers in the American Professional Basketball League (ACPBL). The Bombers won the ACPBL championship and Johnson won the APBL Finals Most Valuable Player award.
In 2012–2013, Johnson joined the National Basketball League of Canada's (NBLC) Saint John Mill Rats. With the Mill Rats, he averaged 10.8 points, 6.0 rebounds, and 1.3 blocks per game.
Johnson then spent the next two years with the Brampton A's in the NBLC. In 2014, Johnson was selected to the All-NBLC Second Team after averaging 14.2 points, 6.2 rebounds and 1.5 blocks per game. He also won the Defensive Player of the Year Award and was selected to participate in the NBLC All-Star Game. In 2015, Johnson averaged 12.4 points, 6.7 rebounds, and was tops in the league with 1.6 blocks per game. He was an All-NBL Canada Third Team member that season and helped the A's reach the NBLC Semi Finals.
On August 3, 2015, Johnson signed a one-year contract with Salon Vilpas Vikings of the Finish League.[4]
On August 1, 2016, Johnson signed with Promitheas Patras of the Greek Basket League.[5] He was officially released from the team on November 28, 2016, in order to attend to personal matters in the States. He then signed with KW Titans in the NBLC.