Byrne worked in archaeology when he left UCD. He maintained his love of his language, later writing the first television drama in
Irish,
Draíocht, on Ireland's national Irish-language television station,
TG4, when it began broadcasting in 1996. Before becoming an actor, Byrne had many jobs, including archaeologist, cook, and Spanish and history school teacher at
Ardscoil Éanna in
Crumlin. He started acting at age 29, In the 90s, his production company Plurabelle Films received a first look deal with Phoenix Pictures. . In 2007, Byrne led the jury of the
Kerry Film Festival. Upon his return to theatre in 2008, Byrne appeared as King Arthur in
Camelot with the
New York Philharmonic from 7 to 10 May, following the footsteps of veteran actors
Richard Burton and
Richard Harris. Byrne was cast in a film adaptation of
Flann O'Brien's
metafictional novel
At Swim-Two-Birds, alongside
Colin Farrell and
Cillian Murphy. Actor
Brendan Gleeson was set to direct the film. an adaptation of Stéphane Osmont's novel of the same name. In 2017, Byrne appeared in
Mad to Be Normal (previously titled
Metanoia), a biopic of the Scottish psychiatrist
R. D. Laing, produced by Gizmo Films.
Walking with Ghosts, Byrne's one-man show based on his memoir of the same title (published by Grove Press in January 2021), premiered at the
Gaiety Theatre, Dublin on 1 February 2022, before playing at the
Edinburgh International Festival. It opened on 6 September 2022 at the
Apollo Theatre in London, marking Byrne's West End debut at the age of 72, in 'a career-best performance', and opened on 26 October 2022 at the
Music Box Theatre on Broadway. ==Personal life==