A woman (Edna Purviance) leaves a charity hospital with a newborn child, and while she passes a church wedding, she leaves her baby with a pleading note in a limousine and goes off to commit suicide. She turns back from suicide at the last moment to return to her child, only to find him missing. The limo had been stolen by thieves who dumped the baby by a garbage can. Charlie, the Tramp finds the baby and, after failing to pass the child on to someone more suitable, raises the child himself. Five years later Edna has become an opera star but she does charity work for slum youngsters in the hope of finding her lost boy. Charlie and The Kid (Jackie Coogan) make an interesting pair, with The Kid breaking windows with stones, which Charlie then comes by to repair. A doctor called by Edna discovers the note with the truth about The Kid and reports it to the authorities, who come to take him away from Charlie. In one of the most touching moments of the film, the Kid has to be pulled out of Charlie's arms by the authorities. Before he arrives at the Orphan Asylum, Charlie steals him back and takes him to a flophouse.
The proprietor reads of a reward for the Kid and takes him from a sleeping Charlie to Edna. Charlie is later awakened from a dream by a kind policeman who reunites him with the Kid at Edna's mansion.
The Kid was Charlie Chaplin's first full-length feature film. It took over a year to produce and was a roaring success. The opening title reads: "A comedy with a smile - and perhaps a tear".