Jack L. Warner Jack L. Warner Jack Leonard "J. L." Warner (August 2, 1892 – September 9, 1978), born Jacob Warner in London, Ontario, was a Jewish Canadian-American film executive who was the president and driving force behind the Warner Bros. Studios in Burbank, California. Warner's career spanned some 45 years, its duration surpassing that of any other of the seminal Hollywood studio moguls. As co-head of production at Warner Bros. Studios, he worked with his brother, Sam Warner, to procure the technology for the film industry's first talking picture. After Sam's death, Jack clashed with his surviving older brothers, Harry and Albert
Jack L. Warner the film's success at the box office, Harry Warner remained concerned about the economic threat presented by the Edison Trust. He subsequently broke with Laemmle and sent Jack to establish a film exchange in San Francisco, while Sam did the same in Los Angeles. The brothers were soon poised to exploit the expanding California movie market. In 1917, Jack was sent to Los Angeles to open another film exchange company. Their first opportunity to produce a major film came in 1918, when they purchased the film rights for "My Four Years in Germany", a bestselling novel that condemned German wartime