With a long-time career as an art teacher and painter of both 'light' and 'dark', Edward Dufner was one of the first students of the Buffalo Fine Arts Academy to earn an Albright Scholarship to study painting in New York. In Buffalo, he had exchanged odd job work for drawing lessons from architect Charles Sumner. He also earned money as an illustrator of a German-language newspaper, and in 1890 took lessons from George Bridgman at the Buffalo Fine Arts Academy.

In 1893, using his scholarship, Dufner moved to Manhattan and enrolled at the Art Students League where he studied with Henry Siddons Mowbray, figure painter and muralist. He also did illustration work for Life, Harper's and Scribner's magazines.

Five years later, in 1898, Dufner went to Paris where he studied at the Academy Julian with Jean-Paul Laurens and privately with James McNeill Whistler. Verification of this relationship, which has been debated by art scholars, comes from researcher Nancy Turk who located at the Smithsonian Institution two 1927 interviews given by Dufner. Turk wrote that Dufner "talks in detail about Whistler, about how he prepared his canvasas and about numerous pieces he painted. . . A great read, the interview puts to bed" the ongoing confusion about whether or not he studied with Whistler.

During his time in France, Dufner summered in the south at Le Pouleu with artists Richard Emil Miller and Frederick Frieseke, and also toured Normandy.

Dufner returned to the United States in 1903 and settled first in Buffalo, where he became a popular teacher at the Art Students League. Of his painting at that time, it was written that "Dufner achieved a considerable reputation in Buffalo with paintings of a dark, monochromatic character that clearly demonstrate his affiliation with Whistler." (Lublin).

In 1907, Dufner moved to Caldwell, New Jersey to be near New York City, where he taught at the Art Students League and again proved to be a popular instructor. However, his painting style began to change drastically from dark to light as he, teaching League summer school at Caldwell, increasingly was influenced by painting outdoors, "en plein aire". In fact, his style change was so pronounced that he became known as "The Painter of Sunshine". (Gerdts 233). Dufner later attributed this change to his seeing an exhibition of painting by Willard Metcalf.

After leaving the Art Students League in 1917, he did teaching at the Carnegie Institute in Pittsburgh and Cooper Union in New York.

Throughout his career, Edward Dufner had been a contributor to exhibitions at the National Academy of Design, beginning in 1904 and ending into the 1940s.