Sometimes considered the first “reality” television show, Candid Camera was produced by Allen Funt. It was first introduced in 1947 as Candid Microphone and then graduated to television on August 10, 1948. Funt was the host (or co-host) of the show until 1993 when he suffered a stroke. His son, Peter Funt, began co-hosting the show in 1987 and is the current producer and host.
The format of the show involved secretly filming them at everyday situations, restaurants, jobs, on the street, etc. There was always a prank involved. When the prank was revealed, the phrase “Smile, Your on Candid Camera” was used.
The show has not run continuously, but as has runs of various lengths. The longest run was from 1950-1967 on CBS.
Here is a clip from an early version involving Woody Allen who was a writer for the show.