John E. Brennan (1865-1940) was one of the most popular screen comedians of the pre-Chaplin era. Hailing from Springfield, Massachusetts, Brennan was successful on the vaudeville stage starting in the 1890s, and hired to be the principal comedian at Kalem Studios in 1912, usually appearing opposite Ruth Roland. He starred in a jaw-dropping 150 one reel comedies over the next four years, with promising-sounding titles like Sherlock Bonehead and Don’t Monkey with the Buzzsaw. A pudgy and dopey scamp, Brennan’s screen character appears to have been not unlike those of contemporaries John Bunny, Fred Mace, or Fatty Arbuckle.
In mid 1915 (around the time Kalem began to unravel), Brennan started to appear in comedies by other studios, such as Sterling, and he even played a supporting part in the 1916 Norma Talmadge drama The Devil’s Needle. Following that he stayed away from screens for four years, returning for the Owen Moore comedy Sooner or Later (1920, directed by Wesley Ruggles), and an independent drama called The Hidden Light (1920). Only 55 at the time, he appears to have retired after that.
To learn more about vaudeville, please read No Applause, Just Throw Money: The Book That Made Vaudeville Famous, and for more on silent comedy film, please read Chain of Fools: Silent Comedy and Its Legacies from Nickelodeons to Youtube.