He first studied at New York"s Art Students League.
His work has been included in almost every major book on American Illustration or the history of the poster. He is also a major figure in the evolution of graphic design. He worked under George de Forest Brush, who was known for his romantic scenes of American Indian life.
He first worked for Harper"s Weekly and later became art director
He developed his own unique style of simplified figures with bold outlines in settings free of extraneous detail. He wrote and published a book titled Holland Sketches, which was published by Scribner"s in 1907.
Penfield lived in New Rochelle, New York, a popular art colony among actors, writers and artists of the period. The community was most well known for its unprecedented number of prominent American illustrators.
His posters were bold and stood out from a distance with great clarity.
Foreign his posters, Penfield utilized simple shapes and a limited palette of colors that lent themselves to the primitive methods of reproduction of the era.
He was one of the founding members of the New Rochelle Art Association which was organized in 1912.