Her first big role was in Casper Meets Wendy where she was the first live-action Wendy. After that success, Hilary was cast as the title character in the Disney television series Lizzie McGuire. Lizzie and Hilary were instant hits! With the success of the series, The Lizzie McGuire Movie released to theaters in 2003 and debuted at #2. Hilary also appeared in Agent Cody Banks and Cheaper by the Dozen in 2003, Raise Your Voice and A Cinderella Story in 2004 and The Perfect Man and the sequel Cheaper by the Dozen 2 in 2005. In 2006, Material Girls co-starring her sister Haylie and the animated movie Foodfight! Will release.