Legendary host of The Tonight Show on American television who was once impersonated by KAOS disguise expert Alexei Sebastian. Sebastian did The Tonight Show for two weeks before they found out. [Mentioned, Episode #11: Too Many Chiefs".]
In addition to the use of his photograph for the above gag, Carson himself appeared briefly in two Get Smart episodes - as the conductor in "Aboard the Orient Express" (#13) and as the herald in "The King Lives?" (#74).