There is no single person who can be considered the "creator" of the art of film animation, as there were several people doing several projects which could be considered various types of animation all around the same time.
Georges Méliès was a creator of special-effect films; he is believed to have invented stop-motion animation. The earliest surviving stop-motion advertising film was an English short by Arthur Melbourne-Cooper called Matches: An Appeal (1899).
J. Stuart Blackton was possibly the first American filmmaker to use the techniques of stop-motion and hand-drawn animation. His 'Humorous Phases of Funny Faces' (1900) is regularly cited as the first true animated film.
A French artist, Émile Cohl, began drawing cartoon strips and created a film in 1908 called Fantasmagorie, which is believed to be the first animated film created using what came to be known as traditional (hand-drawn) animation.