Originally began his career as a noted playwright. His first play, The Beauty Queen of Leenane, was successful enough to be transferred to Broadway in April 1998, gaining a Tony award nomination for Best Play during it's run.
Courted controversy for his comments about disrespecting Theatre in comparison to film, in a 1998 article in BOMB Magazine.
The first film he wrote and directed, Six Shooter, won him an Academy Award for best live action short film.
Won the People's Choice Award at the Toronto International Film Festival for Three Billboards Outside Ebbing, Missouri in 2017.