The film stars Liam Aiken as Owen Baker, as well as the voices of Matthew Broderick, Delta Burke, Donald Faison, Brittany Murphy, Carl Reiner, Vanessa Redgrave, and Cheech Marin as the abundant dog characters in the film.

Owen wakes up the next morning to discover that he can now understand every word Hubble says—including the ominous phrase: "Take me to your leaders."

Owen, Hubble, Connie, and their canine pals set out to whip the other dogs into shape so that they can pass muster.

The Greater Dane hears the message and is left curious by it so she approaches Hubble for his opinion on why the dogs on Earth are subservient to humanity when they should be ruling it.

In June 2002, it was announced Metro-Goldwyn-Mayer (MGM) had greenlit Good Boy, a co-production with The Jim Henson Company about an alien dog coming to Earth from Sirius, the Dog Star, to investigate interstellar reports that his fellow canines have abandoned their original plan to take over the planet.

[2] During the announcement, both MGM and Henson representatives expressed intentions for the film to serve as a franchise with similar expansion to series such as Beethoven, Air Bud, and Balto.

involved digitally altering the facial features of the dogs so that in the film, they appear to be talking or expressing a different emotion (sometimes called CG muzzle replacement).

"[5] Roger Ebert of the Chicago Sun-Times criticized the film's special effects, saying "Sometimes it works to show their lips moving (it certainly did in Babe), but in Good Boy!