In 1877, Conn and his wife, Catherine, relocated to Elkhart, Indiana, where Conn worked various jobs for two years. During this time, Conn sold health care products under the tradename "Konn's Kurative Kream", and invented parts for sewing machines. He also plated and engraved silverware, and manufactured rubber stamps. Drawing from the skills learned at his previous jobs, he invented a cornet mouthpiece with a rubber rim, which began his career in the manufacture of band instruments Conn was an important innovator in the development of modern wind instruments, and established the C.G. Conn Company, a major instrument manufacturer, in Elkhart.
