Fortess became an American citizen in 1923. He studied at the school of the Art Institute of Chicago. He then came to New York where he studied both painting and graphic media at the Art Students League; he also worked under Yasuo Kuniyoshiand at the Woodstock (New York) School of Painting. During World War II he saw active service in Europe, 1942 through 1945.
A lithographer as well as a painter, Fortess's favored subject is landscape. He also has written a number of articles for art periodicals, and is the author of "On the Nature of Things or the Things of Nature" in The Art of the Artist, edited by Arthur Zaidenberg (New York: Crown Publishers, 1951); and "The Comics as Non-Art" in The Funnies: An American Idiom, edited by David M. White and Robert H. Abel (New York: Free Press of Glencoe, 1963). Under a grant from the Unites States Department of Health, Education, and Welfare he assembled a body of eighty recorded interviews with contemporary artists.
Fortess was the recipient of a Guggenheim Memorial Fellowship in 1946. In Academy annual exhibitions he has been awarded the Salmagundi Prize, 1973, and an Obrig Prize, 1979. He has taught at the Art Students League; the Brooklyn (New York) Museum Art School; Louisiana State University; and the Boston University School of Fine and Applied Arts. Fortess resided in Woodstock, NY and received the E. Keith Memorial Award from the Woodstock Artists Association.
