Haydock-Wilson was a member of the British 4 x 400-metre relay team that won bronze at the 2018 IAAF World U20 Championships.[3] In 2019, he won a bronze medal in the 400m at the British indoor senior championships.[4]
At the 2022 World Athletics Championships, Haydock-Wilson qualified from the heats to reach the semi-finals of the men's 400 metres where he ran a new personal best time.[5] He also competed in the mixed 4 x 400 metres relay.[6]
At the 2022 European Championships he won bronze in the finals of the men's 400 metres, and gold in the finals of the men's 4 x 400 metres relay.[7]
In 2023, he became British champion over 400 metres. He was chosen to represent Great Britain at the 2023 World Athletics Championships in Budapest in August 2023.[8]
In April 2024, he was selected as part of the British team for the 2024 World Athletics Relays in Nassau, Bahamas.[9] In May 2024, he was selected to run the 400 metres and 4x400m relay for Britain at the 2024 European Athletics Championships in Rome.[10] Competing at the 2024 British Athletics Championships in Manchester he placed third overall on 30 June 2024.[11]
He was named in the Great Britain team for the 2024 Summer Olympics[12] and was part of the mixed 4x400 team which won a bronze medal in a new national record of 3:08.01.[13][14] He also competed in the men's 4x400m relay at the Games, winning a second bronze medal.[15]
He won the 400 metres title at the 2025 British Indoor Athletics Championships in Birmingham, on 23 February 2025.[16] He was selected for the British team for the 2025 European Athletics Indoor Championships in Apeldoorn.[17] He ran in the men’s 4x400m relay in which the British team placed fourth.[18] He was named in the British team for the 2025 World Athletics Relays in Guangzhou.[19]
On 2 August, he qualified for the final of the 400 metres at the 2025 UK Athletics Championships in Birmingham.[20]
Haydock-Wilson was named in the British squad for the 4 x 400 metres relay at the 2026 World Athletics Relays in Gaborone, Botswana.[21]