Alan Arkin. NYT (archived).
Arkin played guitar, piano, fife and vibraphone, and from 1957-59 he performed and toured throughout Europe with the folk-singing group The Tarriers, who had a hit “Day-O (The Banana Boat Song),” later made more famous by Harry Belafonte. (Arkin and the group sang it and another song in the 1957 film Calypso Heat Wave).
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He tried his hand at starring in a sitcom, Harry, but the ABC show about a hospital wheeler-dealer lasted just seven episodes in 1987. In 2001-02, he played a judge who was soft on criminals on the A&E series 100 Centre Street.
He also played “Jerry Singleton” on three episodes of “St. Elsewhere”, and voiced “J.D. Salinger” on four episodes of “Bojack Horseman”. IMDB.
Unfortunately, I can’t find the bit from “The In-Laws” I really want to use, so how about this one?
And, of course…