The Death of Poor Joe, which dates back to March 1901, was discovered by British Film Institute (BFI) curator Bryony Dixon, in February.
Until now the earliest known Dickens film was Scrooge or Marley's Ghost, released in November 1901.
"It's wonderful to have discovered such a rare and unique film," Ms Dixon said.
"It looks beautiful and is in excellent condition. This really is the icing on the cake of our current celebration of Dickens on Screen."
The Death of Poor Joe will be screened as part of the Dickens bicentennial celebrations on 9 March and 23 March at London's BFI Southbank.
The film organisation said it is also planning to release the footage on a DVD at a later date.
Accidental find
Ms Dixon stumbled across the find as she carried out research on early films of China.
A catalogue entry referred to The Death of Poor Joe, which she recognised as a reference to the character Jo in Bleak House.
After checking on the BFI's archive database, she found the film was listed as part of a collection under an alternative title of Man Meets Ragged Boy, which had been wrongly dated 1902.
The film, which is just one minute long, depicts Joe dying in the freezing snow against a churchyard wall.
As he falls to the ground a local watchman tries to help him and cradles him as he dies.
The footage, which was directed by film pioneer George Albert Smith, was handed to the BFI in 1954, by a collector in Brighton who had known Smith.
The BFI said it believes the director's wife, Laura Bayley, played Joe and the character of the watchman was played by Tom Green. The footage is believed to have been shot in Brighton.
The BFI said the storyline has similarities with Hans Christian Andersen's The Little Match Girl, which features a child dying in the snow and the tragic death of 'Poor Joe', the crossing sweeper in Dickens' Bleak House.
The oldest surviving film featuring a Charles Dickens character has been discovered, in the year of the 200th anniversary of the author's birth.