In 1906, after two years with Pyle, Dunn established his own studio in Wilmington and immediately began a successful career in illustration. He was a prodigious painter, able to produce (on one occasion) fifty-five completed paintings in eleven weeks for various clients. A contemporary described his style in these terms, “He literally attacked a canvas and sometimes I thought he would impale the painting with his brush.” In addition to his illustrations for books, Dunn’s work by then was appearing regularly in such magazines as "Collier's Weekly", "Harper's Magazine", "The Saturday Evening Post", and "Scribner's".