As part of the 2021 Canadian Olympic swimming trials in Toronto, Knox broke the national record in the 200 individual medley event, with a time of 1:58.07. This qualified him for the 2020 Summer Olympics in Tokyo. Knox placed seventeenth in the heats of the men's 200 m individual medley, 0.14 seconds behind Japan's Daiya Seto, and thus missed qualifying to the semi-finals.