Josiah competes in athletics and currently represents UWA Athletics Club, having started when he was 12 years old. His sporting achievements include winning the bronze medal in the U18 100m and the silver medal in the U18 200m at the 2023 Australian Athletics Championships and winning gold in the 100m WA State Championships. At the Trinbago 2023 Commonwealth Youth Games, Josiah qualified for the semi-finals in the 100m and 200m sprints, narrowly missing out on the final of the 200m event by just four-hundredths of a second. His future aspirations include representing Australia at the U20 Junior World Championships, competing in the USA in the college system, and representing Australia at the Commonwealth and Olympic Games.