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).
He schooled at Presentation Brothers College Cork.
He is the only actor playing a villain to appear in all three of Christopher Nolan's Batman films.
As of 2006 he is the most nominated Irish Actor at the Irish Film and Television Awards with 6 nominations.
He used to play in a Frank Zappa-influenced band called 'Sons of Mr. Greengenes' with his brother.