Jack Leonard "J. L." Warner (August 2, 1892 – September 9, 1978), born Jacob Warner in London, Ontario, was a 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 Warner. He assumed exclusive control of the film production company in the 1950s, when he secretly purchased his brothers' shares in the business after convincing them to participate in a joint sale of stocks.
