Yogi Bear was named after legendary New York Yankees catcher Yogi Berra. Because of this, Berra tried to sue Hanna-Barbera for using his name without his permission. He lost the case.
Yogi Bear's voice is an imitation of Art Carney as Norton from The Honeymooners (1955). Yogi even wears a hat with the brim pushed up like Norton.
Snagglepuss's voice was loosely based on character actor Bert Lahr, who played the Cowardly Lion in the Wizard of Oz. When Snagglepuss was subsequently used in a cereal commercial, Lahr requested that a disclaimer be added so people wouldn't think he was involved in the commercial. As a result of this, Daws Butler became the only voice actor to ever receive on-screen credit for a commercial.
The show debuted in syndication on 30 January 1961, and ran for 33 episodes until 6 January 1962, and included two segments, Snagglepuss and Yakky Doodle.