Owen Baker (Liam Aiken) is a 12-year-old who has been working as the neighborhood dog-walker so he can earn the privilege of getting a dog of his own. Owen's hard work pays off when his parents, Mr. and Mrs. Baker (Kevin Nealon and Molly Shannon), let Owen adopt a scruffy Border Terrier that he names Hubble (voice of Matthew Broderick). Owen has little time to make lasting friends, due to his parents' renovation and reselling of houses, so he hopes Hubble will be his best friend.
Owen does have a friend named Connie Flemming (Brittany Moldowan), a girl his age who lives in the neighborhood, but he is also bullied by two boys named Frankie (Hunter Elliott) and Fred (Mikhael Speidel). Soon after the adoption of Hubble, Owen finds out that his new abnormally intelligent dog actually came from outer space. 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 learns that dogs came to Earth thousands of years ago to colonize and dominate the planet. Hubble, who is really named Canid 3942, has been sent by the powerful Greater Dane (voice of Vanessa Redgrave) on a mission from the Dog Star Sirius 7 to make sure dogs have fulfilled this destiny.
The dogs Owen walks include pampered Poodle Barbara Ann (voiced by Delta Burke), rambunctious Boxer Wilson (voiced by Donald Faison), nervous Italian Greyhound Nelly (voiced by Brittany Murphy) and Connie's gassy Bernese Mountain Dog Shep (voiced by Carl Reiner).
Despite the best efforts of Owen and this rag-tag group of neighborhood dogs to convince Hubble that everything is fine with Earth's dogs, Hubble soon discovers the awful truth about Earth dogs: "You're all pets!" Things get worse when Hubble learns that the Greater Dane is headed for Earth to do her own inspection. If things don't look right, all dogs on Earth will be recalled to Sirius.
Owen and Hubble have to work together to prepare the neighborhood dogs for a visit from the Greater Dane and her Chinese Crested Dog henchman (voiced by Cheech Marin). Owen, Hubble, Connie, and their canine pals set out to whip the other dogs into shape so that they can pass muster.
Owen's efforts fail and the Greater Dane recalls all dogs from Earth. Upset, Owen repairs Hubble's communicator and sends him a message declaring how much he loves him. 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. Hubble believes that the dogs and humans have formed a bond of love and loyalty. When asked where his own loyalty lies, Hubble asks the Greater Dane to refer to him as Hubble rather than Canid 3942, showing his bond with Owen. As a result, the Greater Dane sends the Earth dogs back and declares them a separate species. Hubble is allowed to return as well, but on the condition that he removes Owen's ability to communicate with dogs. Owen's parents choose to remain in town for once and Hubble starts to fit in as an Earth dog.Liam Aiken as Owen Baker
Kevin Nealon as Mr. Baker
Molly Shannon as Mrs. Baker
Brittany Moldowan as Connie Flemming
Hunter Elliott as Frankie
Mikhael Speidel as Fred
Patti Allan as Ms. Ryan
Benjamin Ratner as Wilson's Dad
Peter Flemming as Wilson's Other Dad
George Touliatos as Mr. Leone
D. Harlan Cutshall as Mr. Fleming
Brenda M. Crichlow as Mrs. Fleming
Paul Vogt as Dog Catcher
Matthew Broderick as Hubble, a Border Terrier
Donald Faison as Wilson, a Boxer
Delta Burke as Barbara Ann, a poodle
Carl Reiner as Shep, a Bernese Mountain Dog
Brittany Murphy as Nelly, an Italian Greyhound
Vanessa Redgrave as The Greater Dane, a Great Dane
Cheech Marin as The Greater Dane's Henchman, a Chinese Crested
The bulk of the digital effects in Good Boy! 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). These effects were handled by Rainmaker Studios.
The film's domestic total gross was around $37 million, with a worldwide gross of around $45 million. Good Boy! received mixed reviews from critics, earning a 45% rating at Rotten Tomatoes.
Roger Ebert of the Chicago Sun-Times disliked the way Good Boy! was handled. "Sometimes it works to show their lips moving (it certainly did in Babe), but in Good Boy! the jaw movements are so mechanical it doesn't look like speech, it looks like a film loop. Look at Babe again and you'll appreciate the superior way in which the head movements and body language of the animals supplement their speech."
A stop-motion short film animated by the BBC, Hamilton Mattress, accompanied the film's theatrical release.
Good Boy! was released on DVD and VHS on March 2, 2004.