[7] Together with Peter Kavanagh, Harry Cannon, Jimmy White, Jimmy Bermingham, Jeremiah Robinson and Christy Robinson, McCarthy was also a prominent member of the 1927–28 Bohs team which won a quartet of trophies including the League of Ireland title, the FAI Cup, the League of Ireland Shield and the Leinster Senior Cup.
When McCarthy played international football during the 1920s, there were in effect, two Ireland teams, chosen by two rival associations.
As a result, several notable Irish players from this era, including McCarthy played for both teams.
Other members of the Olympic squad included Tommy Muldoon, Joe Kendrick, Paddy Duncan, Johnny Murray and Dinny Hannon.
He made his debut for the FAI XI in their first ever senior international on 28 May 1924, a 1–0 win at the Stade Olympique against Bulgaria.