Amass featured regularly for United's Under-18s and Under-21s during the 2023/24 campaign, and was on the first-team bench for Premier League matches against Liverpool and Bournemouth in April. The defender was also named in the Reds' squad for the FA Cup semi-final against Coventry at Wembley.

Harry, who has been capped at Under-17 level by England, was heavily involved in our 2024 pre-season friendlies, starting all three games of tour and assisting Amad's goal during the 3-2 win over Real Betis in San Diego.

He made his United debut on his 18th birthday, replacing Alejandro Garnacho for the final 20 minutes of our 3-0 win at Leicester City. Amass joined Sheffield Wednesday on loan for the 2025/26 season, on deadline day.