Santa's Little Helper is the Simpsons's family dog. Santa's Little Helper is a purebred Greyhound who was abandoned by his previous owner for losing too many races at the Springfield Downs race track. Homer and Bart found the dog one Christmas Eve and brought him home as the family's Christmas present.

While he is the 'family dog', Santa's Little Helper is beloved by his master, Bart. They spend many hours together playing in the yard and going for walks. Santa's Little Helper also enjoys digging in the backyard and begging for food. He often finds himself in trouble for tearing up furniture, chewing shoes and destroying family quilts. At one point, the Simpsons were ready to give him dog away but decided to put him in obedience training as his one last chance. It took a lot of training and patience, but Santa's Little Helper finally learned the basic commands. Miss Winthorp, the trainer at the obedience school, awarded Santa's Little Helper a degree from the obedience school.

Santa's Little Helper has had many adventures including a romance with a lovely Greyhound that resulted in 25 puppies. The Simpsons decided to put the puppies up for adoption but they were stolen by Mr. Burns. Fortunately, the puppies escaped from Mr. Burns after Bart and Lisa discovered that Burns was going to kill the puppies and use their fur for clothes.

Santa's Little Helper has had some problems with his new family. He was abandoned by the Simpson family for Laddie, a better-bred dog Bart bought from a catalog. He eventually wound up living with a blind man who was later arrested for drugs. Bart came to his senses and tried to take his dog back from the blind man. Bart promised Santa's Little Helper that he would never give him away again. Santa's Little Helper has also had his legs broken by Mr. Burns and had to undergo an urgent operation due to a 'twisted' stomach.

Santa's Little Helper may not be the "Best in Show" however he fits in well and is loved by his family.