Dornan was born in Holywood, County Down, Northern Ireland. He grew up in the suburbs of Belfast, and has two older sisters. His father, Professor Jim Dornan, is an obstetrician who had also considered becoming an actor. Jamie Dornan is a first cousin, twice removed, of actress Greer Garson. His grandparents on both sides of his family were Methodist lay preachers. Dornan was 16 when his mother, Lorna, died.