Duff's mother encouraged Hilary to take up acting classes alongside her elder sister which resulted in both girls winning roles in various local theatre productions.
The siblings became more enthusiastic about the idea of choosing acting as a profession, and eventually relocated to California with their mother, while their father resides at the family home in Houston to take care of their business.
Duff's early career was marked by playing minor roles, starting off with an uncredited appearance in Hallmark Entertainment's western miniseries True Women in 1997.
She also served as an uncredited extra, in writer-director Willard Carroll's ensemble dramedy Playing by Heart in 1998.
, which was to be distributed by Lions Gate Entertainment, but has no scheduled release date.
The same year, Duff reprised her role as Lizzie Mc Guire for The Lizzie Mc Guire Movie. Later that year, she starred in the film Raise Your Voice, her first role in a drama film.However, the plans failed because Duff's representatives said she was not being paid enough for the proposed series.