Chief: "There have been four mysterious deaths in the circus in the past six months . . . Each . . . a violent death during an actual performance."
Max: Hmm. No wonder they draw such big crowds."
- Maxwell Smart - Don Adams
- Agent 99 - Barbara Feldon
- The Chief - Edward Platt
- Carlson - Stacy Keach
- Agent 51 - Gordon Jump (uncredited)
- Pepper Hanlon - Paul Dooley
- Gertrude-Gerald - Mickey Manners
- Raymond the Magnificent - Victor Lundin
The title refers to "The Greatest Show on Earth", the slogan of the Ringling Bros. and Barnum & Bailey Circus, whose name is also parodied in the episode as Farnum and Daley Circus. A film with this name set at that circus was released in 1952.