Dynamic winger Sean Moore joined the Club from NIFL Premiership side Cliftonville in July 2023.

Moore signed a three-year professional contract until June 2026 ahead of the 2023/24 Premier League 2 season.

His performances for Cliftonville in 2022/23 saw the teenager named in the NIFL Premiership Team of the Year and win the NI Football Writers' Association Young Player of the Year award.

Having represented Northern Ireland at U18 level, he switched international allegiance and made his U19 debut for the Republic of Ireland in March 2023, coming off the bench in a UEFA European U19 Championship qualifier against Greece.

Moore's first season as a Hammer saw him tally 23 appearances, four goals and three assists. His maiden strike in Claret and Blue came in a 3-1 Premier League 2 win over Stoke City in January 2024. Prior to that, Moore had helped the Irons reach the EFL Trophy round of 16, making four subsitute appearances. He added PL2 strikes against Tottenham Hotspur and Derby County and also netted in the play-off round of 16 win over Blackburn Rovers in May 2024. At international level, Moore played three times for Northern Ireland U19s, too.

A regular in West Ham's development team in the first half of 2024/25, Moore made his Republic of Ireland U21 debut by starting a 2-0 friendly defeat in Sweden in November 2024.