Chance is a young, immature American bulldog owned by a young boy named Jamie who cares for him very deeply. Given his early life, he was abandoned as a puppy and sent to the pound. Fortunately, he was adopted by Jamie and given a home. His pet comrades are Shadow, a wise, old golden retriever and Sassy, a Himalayan cat who is constantly annoyed by Chance's antics and is usually tortured by him. Due to his immaturity, Chance has a tendency to get himself (as well as his pet comrades) in trouble. He considers Shadow an old fusspot and calls him "old timer", but still has respect for him. His fear of going to "the bad place" seen in the second film leads him and the others to be left behind.
Gallery
Chance with Shadow and Sassy in Homeward Bound: The Incredible Journey
Chance in Homeward Bound II: Lost in San Francisco
Chance stealing and eating Sassy's food
Chance foolishly returning back to the airport lobby leading him and the others to be left behind.
Trivia
In Homeward Bound II: Lost in San Francisco, even though Chance is still called an American bulldog, he was actually portrayed by an American Pit Bull Terrier. This is apparent in that in the first movie, Chance's face was more mushed in, whereas in the sequel, his face was stretched out. American bulldogs have mushed-in faces, while pit bull terriers do not.