[2] Sources: As a freshman at Kentucky in 2013–14, Johnson spent the season backing up teammate Julius Randle and averaged 5.2 points and 3.9 rebounds in 39 games.

As a sophomore the following season, he again played back-up, this time to freshman big man Karl-Anthony Towns and junior Willie Cauley-Stein.

[7] On November 3, 2015, he was acquired by the Oklahoma City Blue of the NBA Development League, the affiliate team of the Thunder.

[8] On November 14, he made his professional debut in a 110–104 loss to the Austin Spurs, recording 16 points, nine rebounds, one assist, one steal and one block in 33 minutes.

[16] On July 23, 2018, Johnson and the draft rights to Tyler Harvey were traded to the Memphis Grizzlies in exchange for Jarell Martin and cash considerations.

[18] On September 11, 2018, Johnson was reported to have signed with Qingdao DoubleStar Eagles of the Chinese Basketball Association (CBA).

[19] On August 23, 2019, Johnson was reported to have played for Anhui Wenyi of the National Basketball League (NBL) and returned with a championship and most valuable player honors.

[24][25] His cousin Michael Murray played college basketball at Coppin State University, where he was selected all-MEAC his senior year.