The movie begins when a box of free puppies are by a grocery store. There are five black puppies and a golden puppy. Soon children come and each puppy is adopted. Pretty soon there are only two puppies in the box. When a little boy and his mother come they take the last black puppy leaving the golden puppy in the box. Left alone in the rain that night the golden puppy flees and grows up a stray. Years later the dog is finally captured by the animal control and is taken to the shelter
13-year-old Calvin Wheeler (Kyle Massey) is the most popular kid at school who collects comic books in his spare time. Calvin's best friend is Raymond Figg (Mitchel Musso), who prefers to be called Figg. He saved Figg's life in the second grade when Figg had an asthma attack, and Figg, very devoted, manages his schedule and occasionally does his homework.
Gotham Man is the name of Calvin's favorite comic. His collection is complete, except for one issue that's ever-so-rare, the first one, it's worth $3,000. When a show-dog runs after Calvin while skateboarding, he finds out that when one wins a dog show, they earn major cash. The cash prize is $5000 which Calvin needs to buy the first issue of Gotham Man.
Calvin goes to a dog rescue shelter and adopts a dog named Tyco. A girl from school and a volunteer at a run down animal shelter, Emily Watson (Kay Panabaker), believes that this had to be another one of the crazy schemes or plans that Calvin has in mind. So she interviews Calvin and judges him a good owner for Tyco, and she says yes when Calvin asks her to the upcoming school dance, until she realizes that he's entering Tyco in a dog show. But there's someone else who wants to make sure Calvin and Tyco lose and that's Preston Price (Carter Jenkins), the stuck-up rich kid whom he and his dog have won two of the past dog shows. He hires people to pretend that they are Tyco's real family, but when the three main characters realize that this is not Tyco's family Figg and Calvin come up with a plan. He convinces Figg to pretend he is selling magazines and to fake an asthma attack. When this happens, Calvin runs into the basement and rescues Tyco while Figg is still acting. Emily forgives Calvin. This is the day of the dog show and they decide to go. Calvin's dad drives them there. Of course they are not prepared so they come up with a last minute routine of Tyco pulling Calvin on his skateboard. They beat Preston by one point. But instead of using that money to buy a comic book he uses the money for good. He gives the money to the shelter so that the dogs can have better homes. In the end, the shelter is saved, and Figg, along with many other people, adopts a new pet.
- Kyle Massey - Calvin Wheeler: The popular school kid and the main protagonist of the movie.
- Kay Panabaker - Emily Watson: One of Calvin's friends and the co-owner of the Animal shelter.
- Mitchel Musso - Raymond Figg: The best friend of Calvin but not that outgoing.
- Carter Jenkins - Preston Price: Winner of past two dog shows and the main antagonist of the movie.
- Judith Moreland - Calvin's Mom
- Mark Christopher Lawrence - Calvin's Dad
- Tyco is about 168 pounds if he is 24 times over the 7 pound limit for pets at Figg's apartment complex.
- Kyle Massey sings the song during the closing credits.
- Tyco's real life name is Jed.
- When Calvin and Emily are playing Nintendo 64, there is no game in the system, but when they're done, there is.
- The "half-pipe" at the dog show was a full pipe.
- When Calvin and Figg were interviewing girls, the first one said she was captain of the cheer leading team. But during the basketball game, she is in the stands, and not with the rest of the cheerleaders.
- At the beginning of the movie, the box of free puppies in front of the store children come and take the black puppies the golden puppy Tyco is left in the box then a boy took one but there was still a puppy left in the box.
- When Calvin is shown skateboarding he is of goofy foot stance, but in scenes featuring the skateboard stunt double, the double is of regular board stance.
- When Tyco pulls Calvin into the water on a leash. Calvin's wheels are bigger when they ride through the grass. That was the only way for them to ride offroad.
- The plot of Life is Ruff is similar to Oliver & Company; in both beginnings, the baby animals (puppies in life is ruff, kittens in oliver & company) are in a box for free. All of the baby animals are picked but the main animal protagonist (Tyco;Oliver) and runs away to become a stray. Later the main animal protagonist is adopted (in Life is Ruff, it's Calvin, in Oliver & Company, it's Jenny) but a rich person temporarily takes them away. At the end the owners and pets are reunited.