He was believed to have been born on April 16, 1889. There is some doubt whether April 16 is actually his birthday. There is also uncertainty about his birthplace: London or Fontainebleau, France. There is no doubt, however, as to his parentage: he was born to Charles Chaplin, Sr. and Hannah Harriette Hill, both Music Hall entertainers. His parents separated soon after his birth, leaving him in the care of his increasingly unstable mother.

In 1896, Chaplin's mother was unable to find work; Charlie and his older half-brother Sydney Chaplin had to be left in the workhouse at Lambeth, moving after several weeks to Hanwell School for Orphans and Destitute Children. His father died when Charlie was 12, and his mother suffered a mental breakdown, and was eventually admitted temporarily to the Cane Hill Asylum at Coulsdon. She died in 1928 in the United States, two years after coming to the States to live with Chaplin, by then a commercial success.

Charlie first took to the stage when, aged five, he performed in Music Hall in 1894, standing in for his mother. As a child, he was confined to a bed for weeks due to a serious illness, and, at night, his mother would sit at the window and act out what was going on outside. In 1900, aged 11, his brother helped get him the role of a comic cat in the pantomime Cinderella at the London Hippodrome. In 1903 he appeared in 'Jim, A Romance of Cockayne', followed by his first regular job, as the newspaper boy Billy in Sherlock Holmes, a part he played into 1906. This was followed by Casey's 'Court Circus' variety show, and, the following year, he became a clown in Fred Karno's 'Fun Factory' slapstick comedy company.

According to immigration records, he arrived in the United States with the Karno troupe on October 2, 1912. In the Karno Company was Arthur Stanley Jefferson, who would later become known as Stan Laurel. Stan Laurel returned to England but Chaplin remained in the United States. Chaplin's act was seen by film producer Mack Sennett, who hired him for his studio, the Keystone Film Company.