Mat appeared in King of Sorrows and stage-managed Miguel Mañara, both with Blackfriars Repertory Theatre. He has worked as an actor, director, stage manager, playwright, and production manager. He is a founding member of State of Play Theatre, for which he appeared in The City That Cried Wolf at 59E59 Theatres. Additionally, he has worked at the Public Theater, The Flea Theater, The Cherry Lane Theatre, The Here Arts Center, The Barrow Group Theatre, The Tank, Impact Theatre, and The Chester Theatre Company. He studied theatre production and acting at Sarah Lawrence College.