The term is best explained by giving examples:
Jack Benny's character on his radio program was notoriously 1) stingy and 2) a bad violin player. In real life, Benny was known as an expert violinist and lavish tipper.
The Blues Brothers, the dark-suited alter egos of Dan Aykroyd and John Belushi, began as a schtick and grew into a record and two movies.
Johnny Carson's schticks include Karnak the Magnificent, an Indian fortune teller who could divine answers to questions sealed in envelopes and kept in a mayonnaise jar on the front porch of Funk & Wagnalls since earlier that afternoon.
Andrew Dice Clay[?] is a crude mysogynist[?] (at least one hopes this is just his schtick.
Rodney Dangerfield don't get no respect.
wikipedia.org dumped 2003-03-17 with terodump