Jay Leno
Before he had his own show, David Letterman would occasionally act as a guest host for “The Tonight Show,” between 1978-1980. In 1982, Letterman would spread his wings on his own show, “Late Night with David Letterman.” Ironically enough, Letterman welcomed future “Tonight Show” host Jay Leno as a guest.
At the time, Leno was a regular on the stand-up comedy circuit, slowly transitioning to a number of minor roles in film and television. As Carson retired in 1992, fans were sure Letterman was next in line to take over “The Tonight Show,” yet lo and behold, the role went to Leno, who hosted until 2009!