Hannah James-Scott was born in Dublin, Ireland. She is the youngest child of Jim and Nora Scott. She has a sister named Sarah who is a hockey coach at a private Catholic school. Her brother is Andrew Scott who plays Jim Moriarty on Sherlock. She has a B.A. Hons in English & History of Art from Trinity College in Dublin. She lives in London with her cousin, Sarah-Jane Scott, who is also an actress.