His father, Jim Dornan, was an obstetrician and gynecologist who, according to Jamie, has delivered over 6,000 babies in his lifetime. His father died on March 15 2021 from COVID-19.
Has three children with Amelia Warner: a daughter named Dulcie, born in Vancouver, British Columbia, Canada, on 21 November 2013; a second daughter, Elva, born in the UK on 16 February 2016, and a third daughter, born in the UK on 31 March 2019.
Was in a relationship with actress Keira Knightley from 2003 to 2005. They met on the set of an Asprey photo shoot in 2003.