On September 27, 2004, the 50th anniversary of The Tonight Show's debut, NBC announced that Conan O'Brien would take over the show in 2009. Leno was still leading the late-night ratings, but O'Brien was promised the show, so that he would not leave NBC. NBC did not want to lose Leno either, and created The Jay Leno Show (2009), the first nightly network primetime talk show. In 2010, due to poor ratings for both O'Brien and Leno's shows, NBC wanted to move Leno's show into O'Brien's timeslot, with O'Brien's "Tonight Show" airing at 12:05 a.m. O'Brien publicly announced that he would rather leave the show than allow that to happen. NBC and O'Brien reached a settlement to allow him to leave the show seven months into his tenure. Leno returned to "The Tonight Show" in March 2010.
The Tonight Show's previous host, Johnny Carson, never once appeared on successor Jay Leno's show. Carson did, however, appear twice on rival late night talk show Late Show with David Letterman (1993) (in a walk-on appearance soon after Letterman's show debuted, and later, in a filmed sketch). In the years following Carson's "Tonight Show" retirement, he reportedly contributed jokes to Letterman's monologues from time to time.
Became the first American nightly talk show to air in High Definition on April 26th, 1999.
Barack Obama's appearance on Folge #17.50 (2009) marked the first television talk show appearance by a sitting President.
Unlike his predecessor, Johnny Carson, whose guest hosts were a staple almost from the beginning, Jay Leno went for a full decade before presenting his first guest host, Katie Couric.