[2] As an adult, McGrath appeared in A Streetcar Named Desire with Alec Baldwin and Jessica Lange as the Young Collector and later portrayed the Emcee, originated by Joel Grey, in the Roundabout Theatre Company's production of Kander and Ebb's musical Cabaret.
He also appeared in The Black Rider (including productions in London, San Francisco, Sydney and Los Angeles), The Legend of Georgia McBride (Lucille Lortel & LAOCC Awards), Hedwig and the Angry Inch, A Fair Country, The Collection, Fat Men in Skirts, The Old Boy, and Amulets Against the Dragon Forces,[4] and Dalton's Back[5] (which received a Drama Desk nomination).
In regional theatre, McGrath has appeared in The Rocky Horror Show (as Frank ‘N' Furter),[6] Romance and Distant Fires (LA Weekly Award).
In The New York Times review of the play, Charles Isherwood wrote, “There isn’t a trace of caricature in his portrayal of the sweetly maternal Tracy”.
[7] McGrath's film appearances include roles in The Chaperone, Boys Don't Cry, The Broken Hearts Club: A Romantic Comedy, The Impostors.