The Lumberjack Song first appeared in episode 9 of Monty Python's Flying Circus, titled “The Ant: An Introduction.” The episode was broadcast on BBC1 on 14 December 1969 during the programme's first series.
The song emerged from a barbershop sketch that needed an ending. According to Michael Palin, the scene and song were devised in roughly 15 minutes after the Python team became stuck while trying to complete the sketch. Palin played the lumberjack, while the famous chorus turned the character's unexpected private fantasy into the sketch's comic climax.
The song was later reused in several forms, including stage performances, films, records and the German Fliegender Zirkus specials. Those later appearances can cause confusion about its original television placement. The episode number is 9, not 19 or 13; the title is also sometimes remembered only by its better-known song segment rather than the episode's deliberately generic-sounding full title.