Duff also starred in the Disney Channel television film Cadet Kelly (2002), which became the network's most watched program in its 19-year history.
In the film, she played the role of a free-spirited girl who struggles in a strict military school.
The film was showcased first at the Cannes and Sundance film festivals.
In the film, Duff portrayed the younger version of a female naturalist, played by Patricia Arquette.
In the same year, Duff was again nominated for a Razzie Award, for The Perfect Man and Cheaper by the Dozen 2.
Later that year, the Duff sisters lent their voices to the computer animated comedy Foodfight!
The plans however failed, because Duff's representatives said she was not being paid enough for the proposed series.
The film received positive reviews and was successful enough to spawn a sequel in which Duff was however not cast.
That year, Duff reprised her role as Lizzie Mc Guire for The Lizzie Mc Guire Movie.
It received mixed reviews, with certain critics calling it "an unabashed promotion of Duff’s image, just as Crossroads was for Britney Spears".
While some critics praised her for appearing in a more mature and serious role than her previous films, the film itself was heavily panned and was not successful at the box office.
Several reviews were indifferent towards her acting performance and were critical of Duff's vocals, with critics pointing out what appeared to be her digitally enhanced voice.