Steiner, the son of Isaac and Lottie Hecht Steiner, was educated in Austria and, after emigrating in 1885, at the Eastman Business College in Poughkeepsie, New York. In 1886 he moved to Alabama to operate a mercantile store in Hamburg, Perry County. In 1888 he joined the Steiner Brothers Bank and later became its president in 1901. He was also president of the Cullman Property Company which invested in real estate in several north Alabama counties, and of the Liberty Graphite Company, the Gulf States Graphite Company, and the Superior Iron Land Company. He was also a vice-president of the Hillman Hotel Company, the Empire Coal Company, and the Burnwell Coal Company.
- Newfield, Morris (November 4, 1911) "The History of the Jews of Birmingham" Reform Advocate
- Cruikshank, George H. (1920) History of Birmingham and Its Environs: A Narrative Account of Their Historical Progress, Their People, and Their Principal Interests. 2 volumes. Chicago, Illinois: Lewis Publishing Company.
- Moore, Daniel Decatur (1922) Men of the South: A Work for the Newspaper Reference Library. Southern Biographical Association
- Leo Keith Steiner, Sr at Findagrave.com