Actors often behave like children, and so we're taken for children. I want to be grown up.

Film
Irons made his film debut in Nijinsky in 1980. On 12 January 2011 Irons was a guest-star in an episode of Law & Order: Special Victims Unit called "Mask". Incest is there to protect us from inbreeding but men don't breed" and wondered whether same-sex marriage might allow fathers to bequeath their estates to their sons to avoid taxation.

In October 2011 he was nominated Goodwill Ambassador of the Food and Agriculture Organization of the United Nations. After receiving classical training at the Bristol Old Vic Theatre School Irons began his acting career on stage in 1969 and has since appeared in many London theatre productions including The Winter's Tale Macbeth Much Ado About Nothing The Taming of the Shrew Godspell and Richard II. Since 2011 he has been starring in the Showtime historical series The Borgias.