Ed McMahon was inspired to say 'Here's Johnny!' by the overemphasized way he had once introduced reporter Robert Pierpoint on the NBC Radio Network program Monitor.

The catchphrase 'Here's Johnny!' ranked top of a 2006 TV Land poll of American TV catchphrases and has been referenced in works ranging from The Shining to Johnny Bravo, a 'Weird Al' Yankovic album, and the Mortal Kombat character Johnny Cage.

After a 1965 incident in which Ed McMahon accidentally ruined one of Carson's jokes on air, he became extremely careful never to step on Carson's material again.

The show's instrumental theme, 'Johnny's Theme,' was a rearrangement of Paul Anka's composition 'Toot Sweet,' which Anka and Annette Funicello had separately recorded with lyrics as 'It's Really Love.'

Carson's mentalist character 'El Mouldo' was a continuation of an earlier character named Dillinger, which he performed in 1955 on The Johnny Carson Show on CBS; Dillinger was a spoof of the real mentalist Dunninger and led to complaints and threats of lawsuits.

Only 33 complete episodes from before May 1, 1972 are known to survive; Carson himself initially encouraged erasing the archives, joking NBC should 'make guitar picks' out of the tapes, and was furious when he later learned they had actually been destroyed.

Because footage was scarce, some surviving fragments include Tiny Tim's on-air wedding, two 1968 Judy Garland appearances, and a poor-quality kinescope/audiotape recording of John Lennon and Paul McCartney's joint 1968 appearance with guest host Joe Garagiola.

According to skeptic James Randi, Carson—himself a former magician—invited self-proclaimed psychic Uri Geller on the show specifically to debunk him by having the crew prepare their own test props without Geller's knowledge, resulting in a famous on-air failure that, paradoxically, boosted Geller's fame.