Chaplin is the story of Charles Chaplin, the famous director and actor that changed film forever. The film starts out with the narrator (played by Anthony Hopkins) and an old Charles Chaplin (played by Robert Downey Jr.) preparing Chaplin's autobiography. This reveals to the audience that the entire movie is the flashbacks of an old Charles Chaplin.
Chaplin then recalls the first time he ever participated in show business. We see Chaplins mother, a poor, defeated woman performing in front of a full theatre of army cadets. Within a few minutes, these military men boo her off the stage, and a young, 5 year old Charles Chaplin walks out on the stage. He sang the same song, and the men love it, and are bewildered that a young 5 year old boy could have that much courage. After this, Charles and his mother return home, and the audience sees the poor, wretched lifestyle that this child is subjected to. Charles, his mom, and his brother Sydney settle down to a meal of fish heads.
After this, the British police come, and seize young Charlie and Sidney to put them to work in a labor house. The two brothers are separated, and quietly descend into the terrible living conditions of a labor hose. After this, we see a teenage Charles Chaplin out of the labor house being guided by his older brother to a new job in show business. Sydney approaches a wealthy man that he works for, and asks him to hire Charlie as a comedian for a play. The man quickly dismissed the idea, but then Charlie starts performing a wonderful routine of slapstick comedy that wins the man over. Sydney also tells Charlie about the problems regarding their mother, and how the loss of both of her sons drove her to insanity. They discuss which care facility they should place her in and how much it would cost. Chaplin is shown performing numerous times in England, and then he meets a girl named Edna Purviance, an actress that travels with his theatre group. He falls in love with her, and asks her to marry him. She says no, and Chaplin leaves to go to America. While in America, Chaplin receives a job from Mack Sennett, who was known as The King of Comedy. Charlie then spends hours in the dressing room picking out what would be known as his Little Tramp outfit. After Charlie develops this renowned character, he instantly becomes famous.
Next, Charlie meets Mildred Harris, a young underage woman who ran away from her home to become an actress. The two get married even through they are not really in love, and it is hinted that the only reason Charlie married her is because he got her pregnant. The two stay together for a while, but eventually divorce. Charlie breaks away from Mack Sennett because of Sennetts demanding wife/co-director, and he leaves with his brother to meet a new financer for his movies. While at this meeting, Charlie meets Lillita McMurray, an actress sitting down eating dinner with her mother. Charlie becomes involved with this woman, and eventually casts her in many of his movies such as The Kid.
Then, Chaplin goes on to divorce this woman and marry another woman named Paulette Goddard, who eventually divorces him because of his obsession with the composing of his movies. Chaplin then made enemies with J. Edgar Hoover at a dinner party, and Hoover continually harassed him throughout his life. When Chaplin leaves America to visit London, he is exiled from America by Hoover, for his scandal of having a baby with an underage woman. While in London, Chaplin realizes it is not really his home, that he really belongs nowhere. Charlie traveled to Switzerland with his final wife Oona Chaplin, and together they lived in exile.