John Llewellyn Lewis (February 12, 1880 – June 11, 1969) was an American leader of organized labor who served as president of the United Mine Workers of America (UMW) from 1920 to 1960. A major player in the history of coal mining, he was the driving force behind the founding of the Congress of Industrial Organizations (CIO), which established the United Steel Workers of America and helped organize millions of other industrial workers in the 1930s.