Unable to find a teaching position after returning to Cleveland, Keller worked for eight years at the Morgan Lithograph Company, where he specialized in designing circus posters. As well as being a master of landscapes and figure studies, Henry Keller devoted much of his talents to depictions of animals, particularly in his original etchings and lithographs. During the 1920s and 1930s, a number of Keller’s etchings and lithographs were commissioned by both the Print Club of Cleveland and the Print-A-Month Club.