Scanlon began playing youth football at
Derby County before joining
Manchester United in February 2021 amidst growing financial uncertainty at
Pride Park. After breaking into the under-18 team towards the end of the 2022–23 season, he became a first-year scholar with the Red Devils in July 2023. During the 2023–24 season he participated in the Red Devils'
2023–24 UEFA Youth League campaign while also making appearances for the under-21 side and training with the first team under
Erik ten Hag. He signed his first professional deal on 23 May 2024, subsequently travelling with the first team on their pre-season tour of the United States. In August, he won the Best Forward award at that year's
Otten Cup youth tournament. After an impressive 2024–25 season with the youth teams, Scanlon was named in a senior matchday squad for the first time on 13 March 2025, in a
UEFA Europa League tie against
Real Sociedad. On 2 February 2026, despite interest from across Europe, Scanlon moved on loan to
EFL League Two side
Swindon Town for the rest of the 2025–26 season. ==International career==