Film:
* The Crying Game (1992): He played the role of Fergus, a character who is pivotal to the film's central mystery.
* The General (1998): A powerful performance as General Patrick C. Cleburne, a Confederate officer during the American Civil War.
* The Wind That Shakes the Barley (2006): A powerful and award-winning film set during the Irish War of Independence, Dillane plays the role of Damien, a central character caught in the conflict.
* The Guard (2011): He plays the character of Gerry Boyle, a corrupt and arrogant Garda Síochána (Irish police officer) in this critically acclaimed comedy-drama.
* The Secret Scripture (2016): He portrays Dr. Grene, a key figure in the life of the main character Rose, in this film based on Sebastian Barry's novel.
* The Last Post (2017): Dillane played Major General Francis "Frank" Bayford in this historical drama series.
Television:
* The Bill (1996-2000): He had a recurring role as Detective Inspector David "Dave" Bishop, a central character in the long-running British police procedural series.
* The Last Kingdom (2015-2020): He played the role of King Æthelred, a significant figure in this historical drama series.
* Peaky Blinders (2017-2019): Dillane played the powerful and menacing character of Chief Inspector Chester Campbell, an antagonist to the Shelby family in this critically acclaimed period crime drama.
* The Crown (2019): Dillane portrayed the role of Group Captain Peter Townsend, a controversial figure in the life of Queen Elizabeth II, in this acclaimed historical drama series.
This list highlights only a few of his significant roles. Dillane has been prolific in his career, with a large number of film and television credits across a variety of genres. He is known for his ability to portray complex and often morally ambiguous characters with depth and nuance.