He played in all grades before progressing to the school's senior team and lined out in various Munster competitions.
[3] McCarthy made his senior championship debut with Sarsfields in a 2–28 to 2–12 defeat of Na Piarsaigh in September 2021.
[4] He quickly became a regular member of starting fifteen and was part of the Sarsfields team that won the Cork PSHC title after a 0–21 to 0–19 defeat of Midleton in the 2023 final.
Success in this grade was immediate with McCarthy claiming Munster and All-Ireland U20HC medals as a member of the extended panel after respective defeats of Limerick and Galway.
[8] McCarthy earned a call-up to the senior team in December 2023 and was at corner-back for a 1–24 to 1–23 defeat by University College Cork in the pre-season Canon O'Brien Cup.