The youngest of seven children, including five brothers, Dunn was the son of a Minneapolis businessman, Thomas Dunn, an Irish-born woollen mill operator who came to Minneapolis in 1869 to run the North Star Woollen Mill. John Dunn was a bookkeeper by trade when he joined the Minneapolis Marines and later worked as a railway postal clerk for the
Chicago Great Western Railway, and for several years, he was Minneapolis district superintendent of postal transportation. At some point, he started managing the Clef Camp resort near
Grand Rapids, Minnesota. Dunn was vice president of the Minneapolis College of Music, while his wife, Marion, was dean of the Minnesota chapter of the
American Guild of Organists. ==References==