What was Buster Keaton's actual first name?

Joseph Frank "Buster" Keaton (October 4, 1895 – February 1, 1966) was an American actor, comedian, film director, producer, screenwriter, and stunt performer. He was best known for his silent films, in which his trademark was physical comedy with a consistently stoic, deadpan expression, earning him the nickname "The Great Stone Face". Critic Roger Ebert wrote of Keaton's "extraordinary period from 1920 to 1929, [when] he worked without interruption on a series of films that make him, arguably, the greatest actor–director in the history of the movies". His career declined afterward with a dispiriting loss of his artistic independence when he was hired by Metro-Goldwyn-Mayer, his wife divorced him, and he descended into alcoholism. He recovered in the 1940s, remarried, and revived his career to a degree as an honored comic performer for the rest of his life, earning an Academy Honorary Award.

Keaton acquired the nickname "Buster" at about 18 months of age. Keaton told interviewer Fletcher Markle that Houdini was present one day when the young Keaton took a tumble down a long flight of stairs without injury. After the infant sat up and shook off his experience, Houdini remarked, "That was a real buster!" According to Keaton, in those days, the word "buster" was used to refer to a spill or a fall that had the potential to produce injury. After this, Keaton's father began to use the nickname to refer to the youngster.