Ryan was born and raised in Fairfield, Connecticut, the daughter of Susan Jordan (née Duggan), a former actress and English teacher, and Harry Hyra, a math teacher. She is of German, Irish, and Slavic descent. She was raised Roman Catholic and attended St. Pius X Elementary School in Fairfield. She has two sisters, Dana and Annie, and a brother, musician Andrew Hyra, a member of the band Billy Pilgrim. Her parents divorced in 1976 when she was 15 years old.