[2] While at college, McCarthy also appeared for USL PDL clubs Ocean City Nor'easters in 2011 and 2012, and Reading United AC in 2013.

[6] Originally signed as a third goalkeeper behind first round draft pick, Andre Blake, and designated player, Rais M'Bohli, McCarthy was given a starting role as a result of injury and poor form, respectively.

He was played mostly during the Union's 2015 U.S. Open Cup run, earning wins in the first four rounds of competition (including two penalty shootouts) ultimately losing in the final.

[10] In December 2019, McCarthy joined MLS expansion side Inter Miami CF ahead of their inaugural 2020 season.

[14] He entered the MLS Cup final against the Union for injured and sent-off goalkeeper Maxime Crépeau in the 117th minute and made two saves during the penalty shootout to win the title for LAFC.