From Time Magazine:

The bastard son of the man who played Mayor McCheese in the old McDonaldland commercials and a french polynesian prostitute, McCheese grew up on the southside of Chicago. After his father lost his job due to legal issues (Mayor McCheese bore too close a resemblance to H.R. Puffinstuff)he would walk around the house in his old torn up costume, had his last name legally changed to McCheese, and beat young McCheese if he didn't refer to him as the Mayor. He later developed a love of supervillainy. At the tender age of 12 he got his first job, as an assassin. He continued to work on his killing skills and became one of the most sought after mercanaries in the world. 5 years ago in a small pacific island nation McCheese started a rebellion with his highly trained troopers the Fry Guys and seized control. He changed the name of the country to The Principality of McCheese and has resided there ever since, ruling the small island nation with an iron fist.

McCheese also posts at Ultimate Central