Charles Chaplin suffered through a divorce from his first wife Mildred Harris while shooting this film.
For the scene in which the Kid is taken from the Tramp and nearly carted away to a workhouse, Charles Chaplin stated in his autobiography that the young Jackie Coogan was made to cry by his father, who told him that if he would not cry in the scene, he would be sent to an actual workhouse.
The main theme from Charles Chaplin's score is based on a theme from Pyotr Ilyich Tchaikovsky's 6th Symphony.
The production company tried to cheat Charles Chaplin by paying him for this six-reel film what they would ordinarily pay him for two-reel film, about half a million dollars. Chaplin took the unassembled film out of state until they agreed to the one-and-a-half million he deserved, plus half the surplus profits on rentals, plus reversion of the film to him after five years on the rental market.
The shooting ratio (the amount of material shot:what appears in the final film) is 53:1, far higher than any other Charles Chaplin film.
The Kid is notable as being the first feature length comedy film to combine comedy and drama, as the opening title says: "A picture with a smile-and perhaps, a tear."
The Kid was Charlie Chaplin's first full-length movie. It was a huge success, and was the second-highest grossing film in 1921, behind The Four Horsemen of the Apocalypse.