The film stars Abigail Breslin, best known as Olive Hoover in Little Miss Sunshine, in the title role, Chris O'Donnell, Joan Cusack, Stanley Tucci, Jane Krakowski, and Julia Ormond.
The story revolves around Margaret Mildred "Kit" Kittredge, an aspiring reporter, writing articles on the typewriter in her attic room. Everything appeared to be fine on her end, and the Great Depression didn't seem to matter much, but things turned for the worse when financial problems forced her family to close down their car dealership business. Jack, Kit's father, has gone to Chicago in search for work, and to make ends meet Kit and her family had to engage in odd jobs such as turning their home into a boarding house and sell chicken eggs to neighbours.
A series of muggings and robberies allegedly perpetuated by hobos were reported across the Ohio valley, and Kit began to investigate on the incidents. On her way, she meets Will and Countee, who live in a hobo jungle near the Ohio River and Erie Lackawanna Railway, and a dog named Grace. Kit writes a story about the camp and tries to sell it to Mr. Gibson, the mean editor of the Cincinnati Register, but he has no interest in the subject. Then, a lockbox containing the Kittredges' money and valuables were stolen, and Will was implicated to be the prime suspect, but Kit believes otherwise. Kit and her friends Ruthie and Stirling then set out to clear Will's name and to accord justice.
It then turns out that one of the boarders, Mr. Berk, along with his accomplices Frederich and Lucinda, the mobile librarian, orchestrated the robberies, and framed the hobos on the basis that they were looked down by society as thieves. Kit becomes a local hero, and as she and her family celebrate with the hobos in Thanksgiving, Mr. Gibson arrives to show Kit that she is in print in Cincinnati's major daily newspaper.
The film, more specifically the German dub, eventually became the basis for Kittredge Parodies. As with other parody themes, characters and settings from the film are used and depicted in a humorous, off-character manner, as part of the Parody Universe.
- This marks the first time an American Girl film was released theatrically, although subsequent films in the series were made as direct-to-video or made-for-television features, and that Kit Kittredge only saw a limited theatre run in the US and was quietly released on home video elsewhere.
- The film was based on an original plot loosely based on Valerie Tripp's central series, with some characters that are exclusive to the film, such as Mr. Berk, Countee and Florence Stone. Kit's brother Charlie was also missing in the film, being mentioned only in passing, along with her Aunt Millie.