2019: Grand Slam tournament debut Johnson made his
ATP Tour and Grand Slam tournament main draw debut simultaneously at the
Wimbledon after receiving a wildcard for direct entry into the men's doubles draw. Partnering compatriot
Evan Hoyt, the pair were defeated in the first round by
Nicholas Monroe and
Mischa Zverev.
2024: First ATP Title, top 100 Johnson reached the top 100 in the rankings at world No. 83 on 29 January 2024 At the back end of the 2024 season, Johnson won his 10th Challenger doubles title at the
Porto Open and his sixth of the season, at the
Saint-Tropez Open, playing alongside
Sander Arends. Once again partnering Arends, Johnson won his first ATP Tour level doubles title at the last tournament of the season at the
Moselle Open, defeating
Pierre-Hugues Herbert and
Albano Olivetti in the final. The following week he was back on the ATP Challenger Tour and won his 12th career title and seventh of the season at the
All In Open in Lyon, partnering
Lucas Miedler to a straight sets win over
Sergio Martos Gornés and
David Pichler in the final. He ended the year inside the top 60 rankings with a career highest rank of No. 58 on 30 December 2024. Johnson reached the top 50 on 31 March 2025, and the quarterfinals in
Dallas, Texas. In April, Johnson and Arends won their second ATP title of the season and first at the
ATP 500 level, at the
Barcelona Open, defeating fellow Brits and former world No. 1 players
Joe Salisbury and
Neal Skupski in the final. At the
French Open, Johnson and Arends reached the quarterfinals, losing to
Hugo Nys and
Edouard Roger-Vasselin. Johnson suffered a broken wrist when he fell during qualifying at the
Queen's Club Championships in June, forcing him to withdraw from
Wimbledon.
2026: Australian Open semifinal Partnering
Jan Zieliński, Johnson reached the semifinals at the
Australian Open, defeating fourth seeds
Marcelo Arévalo and
Mate Pavić in the quarterfinals, before losing in the last four to wildcard entrants
Jason Kubler and.
Marc Polmans in three sets. ==Doubles performance timeline==