On December 13, 2020, Johnson made three solo tackles before exiting in the third quarter due to an injury as the Bears defeated the Houston Texans 36–7.

[21] On January 22, 2021, the Chicago Bears promoted Sean Desai from safeties coach to defensive coordinator after the retirement of Chuck Pagano.

[23] Head coach Matt Nagy paired Johnson with Kindle Vildor as the starting cornerback duo to kickoff the season.

[26] This earned him the highest-rated pass coverage grade (an advanced stat that measures the ability to cover receivers) in the league through that point.

[26] On November 25, 2020, Johnson recorded a season-high six combined tackles (five solo) and forced a fumble during a 16–14 win at the Detroit Lions on Thanksgiving Day.

He finished his sophomore season with a total of 46 combined tackles (37 solo), nine pass deflections, one forced fumble, and one interception in 15 games and 15 starts.

On January 10, 2022, the Chicago Bears fired head coach Matt Nagy and general manager Ryan Pace after finishing the 2021 NFL season with a 6–11 record.

[29] Johnson did not attend the team's voluntary offseason training activities and was subsequently demoted to backup behind Kindle Vildor and Kyler Gordon.

During training camp, Johnson competed to reclaim a starting role against Kindle Vildor, Kyler Gordon, Jaylon Jones, Josh Blackwell, and Lamar Jackson.

[31] Head coach Matt Eberflus named Johnson and rookie Kyler Gordon the starting cornerbacks to begin the season.

Head coach Matt Eberflus named Johnson and Kyler Gordon the starting cornerback duo to begin the regular season.

[34] On October 22, 2023, Johnson made three combined tackles (two solo), two pass deflections, a career-high two interceptions, and returned one 39–yards to score the first touchdown of his career during a 30–12 victory against the Las Vegas Raiders.

He scored the touchdown after intercepting a pass thrown by Brian Hoyer to wide receiver Davante Adams in the fourth quarter.

In Week 11, Johnson collected a season-high six combined tackles (four solo) and broke up a pass during a 19–20 loss to the Green Bay Packers.