His father was a school inspector and his mother was a French teacher.
Attended and graduated from Presentation Brothers College, Cork.
Has a younger brother: Páidi Murphy, a design engineer.
He used to play in a Frank Zappa-influenced band called 'Sons of Mr. Greengenes' with his brother.
Has two younger sisters: Sile and Orla Murphy.
His first name is pronounced "Kill-ian".
He was planning a career in law until he discovered the world of acting.
Although he is a vegetarian, he learned to chop up meat in an abattoir for his role as butcher in Girl with a Pearl Earring (2003).
Auditioned for the role of Batman in Batman Begins (2005). The role was eventually given to Christian Bale. But director Christopher Nolan liked Cillian's audition so much that he gave him a role as Batman's enemy Jonathan Crane/Scarecrow, who is a developing character in this movie.
Though he did not get the role of Batman in Batman Begins (2005), he did get to wear the batsuit during an audition with Christopher Nolan.
Proposed to his wife Yvonne McGuinness while hill-walking in Ireland.
Son Malachy Murphy was born December 4, 2005, weighing 7 pounds and 5 ounces.
Has played two sociopaths in 2005: Dr. Jonathan Crane (Scarecrow) in Batman Begins (2005) and Jackson Rippner in Red Eye (2005).
As of 2006, he is the most nominated Irish actor at the Irish Film and Television Awards with six nominations.
He greatly admires actor Liam Neeson. Looks at him as a surrogate movie father.
Is fluent in English, French, and Irish.
Had been pegged to play the lead in the independent movie, Once (2007). This did not materialize when he was hired for another project. Instead, the role went to Glen Hansard, the person who created the songs for the film.
Good friends with Colin Farrell and Jonathan Rhys Meyers.
Is the only actor playing a villain to appear in all three of Christopher Nolan's Batman films.
Is the first actor to play a DC Comics villain (The Scarecrow) in three consecutive films. Gene Hackman played Superman's nemesis Lex Luthor in three films but did not appear consecutively.
Is a huge fan of Doctor Who (1963).
Agreed to a cameo in TRON: Legacy (2010) because he is a huge fan of the original TRON (1982).
In 2012, he won the Drama Desk Award for Best Solo performance in "Misterman".
Used to be a vegetarian for 12 years. When he started eating meat again, it was venison.
His American accent, when auditioning for Batman Begins (2005), was so convincing that the casting directors had no clue he was really from Ireland.
He still plays music and writes songs but has no intention of starting another band or pursuing it professionally.
An intensely private person, he prefers not to speak about his personal life and did not appear on any live TV chat shows until 2010.
He does not have a stylist or a personal publicist, travels without an entourage, and often attends premieres alone.
Has been in six films with Brendan Gleeson, Sweety Barrett (1998), 28 Days Later... (2002), Cold Mountain (2003), Breakfast on Pluto (2005), Perrier's Bounty (2009) and In the Heart of the Sea (2015).
Sons Malachy and Aran Murphy were both born in Sweden.
Took part in a campaign video in support of the repealing of Article 8 of the Constitution of Ireland that consecrated human lives from their conception and banned abortion.
Is an occasional guest DJ on BBC Radio 6 Music.