Don King did business with Shondor Birns in the Cleveland numbers racket. Birns was the Jewish old-timer who oversaw the numbers for the Cleveland family. If you watch the movie "Kill the Irishman", there's a scene where Danny Greene walks into a black guy with crazy hair about to lay a beating on him when Greene walked in the room and took over administering the beating.

In Rick Porello's book about Greene, they talk of King and how he was a kind of renegade numbers operator who ran his business without taking into regard the existing numbers establishment in Cleveland at the time, black and Jewish. He was given life for killing somebody but got out on a technicality, what followed was boxing's slow death at his hands, haha.