[2] He played a number of sports growing up, including association football, rowing and boxing, before later focusing on rugby union.
[4] Clayton had first tried out American football in 2019, spending time with the newly started NFL Academy in London, although he left the program soon after.
[4][10] He received praise for his pro day performance, measuring at 6 feet 7 inches (2.01 m) and 301 pounds (137 kg; 21.5 st) with a 7-foot (2.1 m) wingspan, while running the 40-yard dash in 4.81 seconds.
[5] He was invited to tryout with several teams and received comparisons to Jordan Mailata, an Australian rugby league player who became a starter for the Philadelphia Eagles.
[4][5] Unlike other IPPP participants such as Louis Rees-Zammit, Clayton was eligible for the 2024 NFL draft due to being within four years of having graduated high school.