The Cocker Spaniel, while known for its exquisite appearance and typically used as a show dog in the United States, is actually a member of the hunting group. The other variety of Cocker Spaniel, the English Cocker, is used primarily as a working hunter. Both American and English Cocker Spaniels are used as hunting dogs and show dogs, however.

Cocker Spaniels date back to the 1300s and probably existed prior without being sufficiently documented. The breed has undergone a lot of changes since then, particularly in the 19th century when Cocker Spaniels were imported to the United States and bred more for show traits than for work. It is assumed that spaniels, as is evidenced by their named, were originally developed in Spain, though gained their initial popularity in England. The original spaniels were bred specifically to aid in hunting and nothing else.

Spaniels, which used to all be considered one breed, were separated into two groups based on their hunting speciality. Water spaniels were retrievers intended to collect downed game in bodies of water. Land spaniels, the group to which Cocker Spaniels belong, both worked as retrievers and flushers, where they would scare game out of the brush for their hunters. The latter category of spaniels is split into two sections. The first group is setting spaniels, which act as pointers and show their hunters where the game is hiding. Cocker Spaniels belong to the second group, which is Springer Spaniels. There are four varieties of Springer Spaniels: the English Springer, Sussex, American Cocker, and English Cocker Spaniel. The Cocker Spaniels are the smallest, with the American Cocker being slightly smaller than the English. Springer Spaniels are used to scare game out of bushes so that their hunters can catch or shoot them. Over the years, and with the development of hunting weaponry, the training of Cocker Spaniels has become more detailed and the job of the Cocker in hunting has become more specific.

The name "Cocker" was derived from the Cocker Spaniel's assistance in the hunting of forest birds called woodcocks. The Cocker Spaniel is also useful for hunting many other small game birds, and has built a strong reputation for its hunting ability in America and England alike.

Though the development of the American Cocker Spaniel has had more emphasis on aesthetic improvement, it is still a good working breed used on many hunts. The American Spaniel Club has a lot of information for those who hope to train their Cockers as hunting dogs.