McCarthy played as a student at St Joseph's CBS Nenagh and captained the school's senior team to their maiden Harty Cup title in 2024.
[4][5] McCarthy also joined the club's senior team in 2023 and was the overall top scorer when Toomevara were beaten in the 2024 SHC final.
[6] McCarthy first appeared on the inter-county scene for Tipperary at the age of 17 as a member of the minor team that won the All-Ireland MHC title after a defeat of Offaly in 2022.
[8] McCarthy's performances at school and inter-county underage levels resulted in a call-up to the senior team's training panel in mid-December 2024.
[9][10] On 26 January 2025, he made his senior debut for Tipperary, scoring 1-6 in a 3-25 to 2-16 win against Galway in the opening round of the 2025 National Hurling League.