Using a name that was previously used for a hardtop edition of the 1956-1960 Cadillac Eldorado model, the Cadillac Seville became a nameplate on its own when it was released in mid-1975 as a 1976 model. Though it was largely based on GM's X-body platform (Buick Skylark, Chevrolet Nova, etc), it was differentiated enough to be given its own unique "K" body designation. This new Seville was Cadillac's answer to the the rising popularity of luxury imports in the USA from Europe, such as Mercedes-Benz and BMW. Historically, these imported luxury cars had been cheaper, less luxurious and significantly smaller than Cadillacs, but over time they had evolved, and had become more luxurious and eventually even more expensive than Cadillacs. It became obvious that the traditional American automotive paradigm of "bigger equals better" was no longer in full effect in the marketplace.
The Seville was to be simultaneously the smallest and the most expensive Cadillac in the line-up, turning Cadillac's traditional marketing and pricing strategy on its head. The Seville maintained its position as the most expensive mass-produced American sedan throughout its run.
The Seville would undergo several generational transformations during its tenure from 1976-2004 when it was replaced by the STS, an alphanumeric designation that was previously a Euro-inspired option package available for the Seville (Seville Touring Sedan) available since the 1988 model year. The elimination of traditional names for Cadillacs and the subsequent alphanumeric model designations for the line-up was thought to be in keeping with the naming conventions of Cadillac's foreign competitors which universally use alphanumerics for their model nomenclature.