Film:
* The Wind That Shakes the Barley (2006): He played "Paddy" in this Academy Award-winning film, a powerful drama set during the Irish War of Independence.
* In Bruges (2008): Colm played "Ken," a hitman alongside Brendan Gleeson and Colin Farrell.
* The Guard (2011): Another Irish crime comedy, where he played "Sergeant O'Connell."
* The Secret of Kells (2009): He voiced the character of "Aidan" in this Oscar-nominated animated film.
* Sing Street (2016): Colm played "Barry" in this coming-of-age musical about a Dublin boy who forms a band.
Television:
* The Tudors (2007-2010): He played "Thomas Cromwell," a key historical figure in the series.
* Peaky Blinders (2013-2022): He portrayed "Father John Hughes," a recurring character.
* The Last Kingdom (2015-2022): Colm played "Father Pyrlig," a pivotal figure in the Saxon-Viking conflict.
* Game of Thrones (2011-2019): He played "Grand Maester Pycelle" in the fantasy series.
* Vikings (2013-2020): Colm played "Bishop Heahmund," a fierce warrior-bishop.
This is just a sample of Colm Hefferon's impressive filmography. He has also appeared in many other films, television series, and stage productions, demonstrating his versatility and talent as an actor.