Other musical stage roles have included: Max in Cabaret; Sir Lancelot in Camelot; Thomas Inkle in a 1997 revival of Inkle and Yarico; the Phantom in Ken Hill's Phantom of the Opera; Ivan Molokov in Chess and Sweeney Todd in Sweeney Todd: The Demon Barber of Fleet Street.

He then received a full scholarship to Stephens College, Columbia, Missouri in the United States where he gained his Bachelor of Fine Arts degree in theatre and music.

[3][4] Parts that he performed at their summer stock theatre, the Okoboji Summer Theatre, and the college's Macklanburg Playhouse included: a soloist / ensemble member in a biographical revue of Cole Porter; Max in Cabaret; Tom in Brigadoon; Dominique in The Baker's Wife; Marco in A View from the Bridge; and Count Carl Magnus in A Little Night Music.

[3] Roles included: a member of the ensemble in Rigoletto; Patrick Dennis in Mame; Tom Trainer in No, No, Nanette; Sir Lancelot in Camelot;[5][6] and The Red Shadow in The Desert Song.

[8] He began his connection with Les Misérables in 1990, initially playing Combeferre and then the Factory Foreman and understudy to the part of Javert at the Palace Theatre in London.

[9][10] In November 1994 McCarthy appeared in a new musical, Out of the Blue, with Meredith Braun, who had previously starred alongside him as Éponine in Les Misérables in Manchester.

[20] He also played the role of Javert in concert productions: in 1997, at the Chelmsford Festival; in 2002 at the Globe Arena, Stockholm;[21][22] and in 2004 for the Queen and her guests at Windsor Castle.

[36][48] Other broadcast work includes: the role of The Gypsy King in The 10th Kingdom;[5][28] the role of Second Priest in a TV film adaptation of Jesus Christ Superstar for PBS's series Great Performances,[49] which was also released as a DVD;[50] and he sang Summertime, Nature Boy and If Ever I Would Leave You on BBC Radio 2's Friday Night Is Music Night, presented by Ken Bruce.