William L. Longyear studied at the Art Students League, Columbia University and the Pratt Institute.
Longyear worked at the Museum of Science and Industry in New York and as an illustrator at Fortune magazine. He also designed board games and authored a number of textbooks on advertising design and typography.
By 1940, Longyear was on the faculty at Pratt Institute in Brooklyn, where he served as Chairman of the Department of Advertising Design and as Associate Dean. There is currently a scholarship for design students at Pratt named in his honor.