Who is king beef on the Martin show?

There's no character named "King Beef" on the Martin show. It's likely you're thinking of a different character or show.

Perhaps you're thinking of:

* King Tut, played by Tisha Campbell-Martin, Martin's wife on the show.

* Big Red, the character played by T.C. Carson, who was often the target of Martin's jokes.

Could you provide more context about the character you're asking about? That might help clarify things.