He is based on the character of the same name from the story by E.T.A. Hoffman and the ballet by Pyotr Ilyich Tchaikovsky.
In both the original story and the ballet, he was the main villain. Here, he is a heroic figure, while The Sugar Plum Fairy is the main villain instead (who, in turn, was a heroic figure in the original story and in the ballet).
In the book, he actually had seven heads. In the film, he has only one like all real-life mice.
In the film, he and his subjects become one huge mouse to defeat enemies bigger than they which is not at all in the book.