By that stage, Costello had progressed to adult level with Cappawhite and won three West Tipperary SHC titles between 2000 and 2005.
He ended that competition with a winners' medal after Tipperary claimed the title after a 1–19 to 0–17 defeat of Clare in the final.
[7] At inter-provincial level, Costello also earned selection to the Munster team and also won a Railway Cup medal in 2001 after a six-point defeat of Connacht.
Costello became a selector as part of Brendan Cummins's Tipperary under-21 hurling management team in October 2022.
[9] During his tenure, the team won the Munster U20HC title before losing the 2024 All-Ireland under-20 final to Offaly.