Junior During the
2018–19 season in his first season with the
Trail Smoke Eaters of the
British Columbia Hockey League (BCHL), Johnson recorded 20 goals and 26 points in 57 games. During the
2019–20 season, he recorded 41 goals and 60 assists in 52 games and won the Brett Hull Trophy as the league's leading scorer. Following an outstanding season, he was named BCHL First-Team All-Star, BCHL Most Sportsmanlike Player, BCHL Most Valuable Player, and Canadian Junior Hockey League Forward of the Year.
Collegiate Johnson began his
collegiate career for the
Michigan Wolverines during the
2020–21 season. On January 8, 2021, Johnson recorded a career-high five points in a game against the
Michigan State Spartans. He became the first Michigan player to record five points in a game since
J. T. Compher on March 18, 2016. He was subsequently named the
Big Ten Conference First Star of the Week for the week ending January 13, 2021. He finished his freshman season with nine goals and 18 assists in 26 games. He ranked second in rookie scoring in the Big Ten Conference and third in the nation in rookie points per game. Following the season, he was named to the All-
Big Ten Freshman Team. During the
2021–22 season in his sophomore year, he recorded eight goals and 29 assists in 32 games. He finished fourth in the nation in assists per game and ranked 16th in points per game.
Professional On July 23, 2021, Johnson was selected in the first round, fifth overall, by the
Columbus Blue Jackets in the
2021 NHL entry draft. On April 8, 2022, Johnson signed a three-year, entry-level contract with the Blue Jackets. He made his NHL debut on April 13, 2022, in a game against the
Montreal Canadiens. He finished the
2021–22 season with three assists in nine games. Johnson scored his first career NHL goal on October 22, 2022, against
Tristan Jarry of the
Pittsburgh Penguins. On July 27, 2024, the Blue Jackets signed Johnson to a three-year, $5.4 million contract extension with an annual average of $1.8 million. ==International play==