McCarthy was born in Ann Arbor, Michigan, and is set to return to the Midwest after an impressive career in Ireland. Most recently, the scrum half appeared in 16 contests for Leinster during the 2022-2023 season.
McCarthy has played 85 games with 16 starts across nine seasons with Leinster and Munster. The 5-foot-11, 185 pound scrum half has totaled 2,195 minutes with 25 points scored on five tries for the two Irish teams.
The scrum half first appeared for Leinster in their Under-16 and Under-18 teams before joining their sub-academy in 2013. He was called up to their full academy side prior to the 2014-2015 season.
McCarthy made his debut for Leinster’s senior side during the 2015-2016 campaign with three appearances on the year. He suited up four times during their next season before earning promotion to their senior squad ahead of the 2017-2018 campaign. The scrum half scored three tries in his 21 appearances that year.
He signed on with Munster prior to their 2019-2020 season and spent two years there before making a return to Leinster.
He was called up into the USA National team camp this past summer and earned three caps for the Eagles. McCarthy made two starts for the team and scored a try on his debut against Romania, a 31-17 win for the United States.