Warner, Jackin full Jack Leonard Warner  ( born Aug. August 2, 1882 1892 , London, Ont., Can.—died Sept. Ontario, Canada—died September 9, 1978 , Los Angeles, Calif.California, U.S. )  American motion-picture producer, best known of the four brothers—Harry (1881–1958), Albert (1884–1967), Samuel (1888–1927), and Jack—who founded Warner Brothers Pictures, Inc. (q.v.), which became one of Hollywood’s Big Five studios.

The sons of an immigrant Polish cobbler and peddler, the brothers gave traveling shows with their own film projector, ran a movie theatre in Lancaster, Pa.Pennsylvania, for a couple of years, and then moved into film distribution. The Warner Bros. Brothers studio was established in 1923. Jack Warner, as vice - president in charge of production, ran Warner’s movie industry like a factory, with discipline and order. He personally supervised the selection of story material, the selection of producers and directors, and the search for acting and directorial talent. Economy-minded, he anticipated repeated use of sets, costumes, and props in reassembled combinations. He also, however, sought authenticity and tried to see to it that regional or national modes or customs were accurately portrayed.

Jack Warner was president as well as head of production at Warner’s from 1956; when the studio was taken over in 1965 by Seven Arts, he became president of the Warner-Seven Warner–Seven Arts Studio but retained his own independent production company. He personally produced My Fair Lady (1964) and Camelot (1967). He retired in 1972.