Johnson played college football at Southern University as a cornerback and return specialist. He was named First-team All-SWAC as a cornerback in three consecutive seasons, from 2015-2017, and was named Second-team All-SWAC as a return specialist in 2017.[1][2] Johnson was also named Third-team FCS All-American as a cornerback in 2016.[3]
Johnson was invited to the 2018 Senior Bowl, becoming the first player from that school to receive an invitation in two decades.[4]
Johnson was placed on the physically unable to perform list to start the 2019 season while recovering from injury. He was activated on December 10, 2019.[14] He started two games before being placed on injured reserve on December 24, 2019.[15] He re-signed with the team on March 23, 2021,[16] but was waived on August 31, 2021,[17] and re-signed to the practice squad the following day.[18] Johnson was signed to the active roster on October 5, 2021.[19]
Johnson re-signed with the team on March 23, 2022.[20] He was waived on August 30, 2022, and signed to the practice squad the following day.[21][22] He was promoted back to the active roster on October 25, 2022.[23] In Week 9 of the 2022 season, Johnson recorded his first career interception against the Minnesota Vikings off a pass deflected by Benjamin St-Juste in the end zone.[24]
Johnson signed a two-year contract extension with the Commanders on March 16, 2023.[25] Following first round rookie, Emmanuel Forbes, being benched in Week 5 and downgraded on the team's depth chart, Johnson was elevated into the defense's starting lineup.[26][27] He was released on December 13.[28]