Coming out of high school, Weber State was the only college that offered Johnson a football position, so he accepted it.[2]
Johnson started five games as a freshman at Weber State, and was a full-time starter thereafter. As a sophomore, he set a school record with 12 pass break-ups, and then tied the record the following season as a junior. As a senior in 2017, he totaled three interceptions, nine pass break-ups, and 49 tackles, earning the Big Sky Defensive Player of the Year award[3] and consensus First Time All-American honors.[4]
Johnson was selected by the Buffalo Bills in the fourth round of the 2018 NFL draft with the 121st overall pick.[7] On May 11, 2018, he signed his rookie contract.[8] Against the Green Bay Packers in week 4, Johnson recorded his first career sack and forced fumble, taking down quarterback Aaron Rodgers with a strip-sack.[9] Johnson recorded his first career interception the following week against the Tennessee Titans, picking off Marcus Mariota in the 13–12 victory.[10] He was placed on injured reserve on December 11, 2018, after undergoing shoulder surgery.[11]
In Week 14 against the Pittsburgh SteelersonSunday Night Football, Johnson intercepted a pass thrown by Ben Roethlisberger and returned it for a 51-yard touchdown during the 26–15 win.[13]
In the Divisional Round of the playoffs against the Baltimore Ravens, Johnson intercepted a pass thrown by Lamar Jackson in the Bills' endzone and returned it for a 101-yard pick six during the 17–3 win.[14] This return tied the longest in NFL playoff history with George Teague.
On October 9, 2021, Johnson signed a three-year, $24 million contract extension with the Bills.[15]
After a second-team All-Pro season in 2023 as a slot cornerback, Johnson signed a three-year, $31 million contract extension with the Bills through the 2027 season.[16]
