Amanda Seyfried was born and raised in Allentown, Pennsylvania, to Ann (Sander), an occupational therapist, and Jack Seyfried, a pharmacist. She is of German, and some English and Scottish, ancestry. She began modeling when she was eleven, and acted in high school productions as well as taking singing lessons.

More soap work followed as she completed her schooling and had already secured a place at Fordham University when she was offered a role in the Tina Fey-penned teen comedy Mean Girls (2004). She deferred her university education to complete the film. More television work followed, raising her profile across America, while her appearances in Mamma Mia! (2008) and Red Riding Hood (2011) helped establish her international fame.