He first got his big break when he became Zim's opponent in the Skool Election after the last Student President had a mental breakdown (characterized by the Skool as a 'loss of Skool spirit'), and was supported by Dib. With limited intelligence, he relied on Dib's help to win the election, until his mindless confidence and idiocy took over.
Nevertheless, he won, and was subsequently brainwashed to act intelligent, speak with a British accent, and praise the Skool constantly.
Willy is a large, bald male who wears a light green, undersized shirt with a cat on it, and usually has his tongue sticking out of his mouth (causing him to slur his speech often).
There is a kid in the original pilot who strongly resembles him.