Born in Richmond, Quebec, Sennett was a son of Irish immigrants. His father was a blacksmith.
Sennett was a singer, dancer, clown, actor, set designer and director for Biograph, and founded Keystone in 1912 together with Adam Kessel. Many important actors were discovered by him and started their career at Keystone. Those include Charlie Chaplin, Raymond Griffith, Gloria Swanson, Ford Sterling, the Keystone Kops and many more.
Sennett first acted in films at Biograph studios, playing low comedy parts, usually oafish rural types. His chance at directing came in 1912 at the new Keystone brand. His fast-paced knockabout style and good distribution as part of the Mutual program, insured recognition of the Keystone trade mark as well as his stars and his own name. In a very short space of time, that name became synonymous with screen comedy. In fact, when he left to produce independently, to be released by Paramount in 1917, he didn't fight to take the Keystone Brand with him, his own name proved more valuable.
Into the 20's, his short subjects were in demand, with stars such as Billy Bevan, Harry Gribbon, Vernon Dent, Alice Day, Ralph Graves, Charley Murray, and Harry Langdon. He even mounted a few features with his brightest stars such as Ben Turpin and Mabel Normand.
In an ultimately poor business move in the mid 1920's, he moved over to Pathe distributors, which although had a huge exchange, made bad decisions, such as handling too many comedies at once, including Sennett's main competitor, Hal Roach. In 1927, Hollywood's two top studios, Paramount and MGM, seeing the profits coming in from short-subject companies like Pathe and Educational, both got back into their own distribution and production after several years. Roach signed up with MGM, leaving Sennett now by himself at Pathe, but they were now on hard times because the hundreds of exhibitors that used to take their shorts had switched to the new MGM or Paramount subjects.
Though Sennett occasionally experimented with color and managed to be the first to get a talkie short subject on the market in 1928, the huge overall comedown in quality really showed. The later silents and talkies were pretty poor. Though he had a popular series with up and coming star Bing Crosby, most of his stars, as always, deserted him for greener pastures. Dreadful films such as "Hypnotized" with blackface comedians Mack and Moran ended his career in the early 1930's.
He didn't lose everything, but he was no longer in film. He sold his backlog of films to Warner Brothers in the 1930's. They pretty much used it for occasional stock footage, but basically destroyed them when they took up too much space. Today there are many Sennett films, especially from his most well financed period in around 1917-27 that don't exist.
In sum, Sennett's style made our great grandfathers laugh, but he was loath to ever change his formula of chases and messy fights. It was very nearly the same from his first to his last, aimed at the less demanding in the audience. Today his name is still highly recognizable, even to those who will have virtually no contact with his films, and the term "Keystone Kops" has become part of the language to describe incompetent buffoons with some supposed authority. MJ
He died in Woodland Hills, California and was interred in the Holy Cross Cemetery in Culver City, California.