Costelloe joined Burnley from Galway United in 2021. He progressed through the U21 team and made his senior debut for Burnley in the Championship in July 2022.
During his time with Burnley, Costelloe had loan spells at several clubs, including Bradford City, St Johnstone, Dundee, Accrington Stanley, and Northampton Town.
Costelloe expressed his excitement about joining Wigan Athletic in an interview. He mentioned that his family was present during the transfer process and was impressed by the club's stadium. Costelloe is looking forward to working with the team and achieving their goals, which include returning to the Championship.
He also mentioned that he was inspired by the progress of other strikers who have worked with Wigan's coach. Costelloe hopes to follow in their footsteps and develop his skills under the coach's guidance.
