The Haddorff Piano Company was established in 1901 by Charles A. Haddorff in Rockford, Illinois. Their factories were located at 55 Ethel Street. Haddorff was a large-scale manufacturer, and they built pianos for several other prominent piano manufacturers including Bush & Gerts and Clarendon. During the 1920's era, the firm was controlled by the Krakauer Brothers Piano Company. One of Haddorff's most famous contribution to the piano industry was their introduction of the 'Vertichord' spinet piano in the 1930's. After World War 2, the Haddorff name was bought by Conn, who shortly thereafter sold the Haddorff name to Kimball. Kimball discontinued the Haddorff piano brand name around 1960.