Dewey Largo is the music teacher at Springfield Elementary.
Mr. Largo is the only teacher Lisa hates as she said Mr. Largo is living proof any music can have the soul sucked right out of it. He makes the children play very boring music and claims that fun music is Devil's music. He is the head of the Talent Restriction Committee in the comics. He is a mean spirited individual and stifles Lisa's creativity thus causing Lisa to play jazz with her saxophone as seen on the opening credits.
He once took over for Groundskeeper Willie for a short time and is even more incompetent as a groundskeeper than a music teacher as he ends up driving a tractor up onto the school roof.
Many episodes imply he may be a homosexual and one episode had him planning to get a sex change operation. He also seems to love Xylophones as he refuses to give up his after the city bans them.