I can find three appearances.
Buddy Rich appeared on The Tonight Show 43 times.
Laura Bush appeared eight times on The Tonight Show, once with Jimmy Fallon and the rest with Jay Leno.
Christopher Walken has hosted Saturday Night Live six times as of April 27, 2008Below is a list of the times he has hosted copied from http://www.celebratingchristopherwalken.com/snlshows.htmOriginal Run Date: Musical Guest April 6, 2008: Panic at the Disco February 22, 2003: Foo Fighters May 19, 2001: Weezer April 8, 2000: Christina Aguilara January 13, 1996: Joan Osbourne October 24, 1992: Arrested Development January 20, 1990: Bonnie Raitt
Yes, he appeared on The Tonight Show starring Johnny Carson four times but all his guest spots were prior to his presidency.
The Tonight Show has aired 11,461 times as of this writing. It first aired in 1954 and is the longest-running talk show in history. Its hosts have been Steve Allen, Jack Paar, Johnny Carson, Jay Leno and, most recently, Jimmy Fallon.
gababcbagabagba repeat 3 times
David Steinberg
2 times
4 times
Christopher Columbos went on four expeditions
Christopher Columbus
Bob Newhart