Martin’s theatre work includes Harry Potter and the Cursed Child, Once, Mamma Mia! (West End and International), Our Ladies of Perpetual Succour (National Theatre of Scotland), War Horse, The Light Princess, Caroline or Change, Jerry Springer The Opera (all at the National Theatre), Sound of the Underground (Royal Court), Jedermann (Salzburg Festival), Abba Voyage (Abba Arena).

Martin won the Tony, Grammy and Olivier award for his work on Once, and a Golden Reel Award for Mamma Mia! The Movie.