The movies came first. The cartoon derived from the wild popularity the animated title sequence critter generated (far more than the film itself). The Pink Panther was a huge jewel sought by a notorious thief and Sellers' Clouseau was the bumbling cop "hero". Unfortunately, the character was eclipsed in popularity by aforesaid critter (who oddly enough, lent the movie series HIS name by association as the ongoing animated title sequence STAR; the jewel faded from the general movie-going consciousness). When the public demanded more Panther sightings, Clouseau came with the package.