A dog and pony show started out just as its name suggests. During the end of the 19th and start of the 20th century, these shows originated as small traveling circus troupes that stopped off at small towns and rural areas to showcase performances. The shows were often held in open public arenas such as the racetrack or municipal park, and featured shows by live dogs and ponies doing tricks.
These traveling troupes were showcased particularly in the Midwest, and were mainly run by men seeking their fortunes. Often the dog and pony show was operated on a shoestring budget, with nothing more than a simple band, the ringmaster, and the presence of several performing dogs and ponies, which were the only main attraction. During the period in which their popularity peaked, the most famous troupe was "Professor" Gentry, which actually consisted of a band of four brothers. "Professor" Gentry was only one of few shows that eventually evolved into a full-scale circus with more than 50 dogs and horses. Two other famous dog and pony shows included Sipe & Polman and the Harper Brothers.
Because the dog and pony show was more style than substance, respectability for these performing troupes waned. The shows were seen as gaudy due to their meager budget and ostentatious showcasing of generally unimpressive acts. As a result, it can be seen today as the predecessor of a "proper" circus. Into the 1950s, it devolved from an actual show to more of a sideshow, especially for children, so that they could ride the ponies and pet the dogs while the main attraction ran something more grandiose.
A "dog and pony show" as a term used in the modern sense has lost its original meaning altogether. It is frequently used to mean a lamely contrived visual presentation, photo opportunity, political speech, or sales pitch, mostly for promotional purposes. This shift in definition parallels the history of the rise and eventual downfall of the show's success.