Willie hails from North Kilttown. Not only is he the janitor at Springfield Elementary, he seems to live there too. He had a shack which Bart destroyed...now he probably lives somewhere in the basement of the school. He bathes in the cafeteria kitchen using an abrasive cleaner and SOS Pads.

Willie was once deported, but managed to find his way back to Springfield.

Occasionally auditions his vocal talent by singing "Ach! Doontoon".