In 1795, Mr. Fuller of Rosehill Park, Hastings in East Sussex, England began breeding gundogs to work in districts where the terrain was rough and the undergrowth very dense which meant that a spaniel was needed which could give tongue or to alert the sportsman of the quarry. Fuller crossed various breeds such as Relf and the liver and white Norfolk Spaniels, (both of which are now extinct), the Field Spaniel, and possibly some early springer spaniels. The Sussex was bred specifically to inherit the barking ability (giving tongue)  that was not common in most spaniel breeds during this era This is seen as an asset in the field for this particular breed, however, the giving of tongue  is frowned upon in every other hunting spaniel breed.

Always slow dogs, the Sussex spaniel has been superseded by the faster, leggier  spaniel breeds of today.  The colouring of the Sussex is a throw back to their original bloodline, particularly the Relf spaniels that were of a golden liver hew.  The coat of the Sussex is soft and smooth with ample feathering around the legs.  The feet are un-proportionally large and would be of a distinct advantage in wet and heavy soil conditions.