The Haddorff Piano Company was founded in Rockford, Illinois, in 1901–02 by Charles A. Haddorff with backing from P. A. Peterson, and it shipped its 100,000th piano in 1923. It also built pianos for other firms such as Bush & Gerts and introduced the small Vertichord upright in the 1930s. Conn bought the name after World War II and sold it to Kimball, which dropped it around 1960.