[1] He competed in the men's 50 metre breaststroke event at the 2018 FINA World Swimming Championships (25 m), in Hangzhou, China.

[6] Grayson competed in the men's 50 metre breaststroke event at the 2018 FINA World Swimming Championships (25 m), in Hangzhou, China.

[8][9] Grayson was named to the team Australia rosters for both the 2022 World Aquatics Championships and 2022 Commonwealth Games based on his times and place-finishes.

[11] The following month, Bell ranked first in the preliminaries of the 50 metre breaststroke on the first day of swimming at the 2022 Commonwealth Games, advancing to the semifinals with a time of 27.63 seconds.

[12][13] Later the same month, Grayson won the silver medal in the 50 meter breaststroke at the 2022 Australian Short Course Swimming Championships with a time of 26.45, sharing the podium with two Americans.