He was born in London, England on 29 April 1957. He had dual citizenship - British and Irish. He is the youngest of Cecil Day-Lewis' four children and the younger of Jill Balcon's two children. His sister, Tamasin Day-Lewis, is a television chef. Day-Lewis married Rebecca Miller (the daughter of Arthur Miller) in 1996. From another relationship Day-Lewis has one son. With Miller, he has two sons.