 His partnership with Chicago mobsters led him to be named "...the most powerful lawyer in the world" by the FBI.Sidney was born into a Jewish family, with four siblings, in Chicago's West Side Lawndale neighborhood, on June 6, 1907.His parents were Harry Korshak (1876–1931) and Rebecca Beatrice Lash (Lashkovitz, Laskowitz) (1883–1963), who were married on July 15, 1902 in Chicago.