Painter, printmaker, and sculptor Edwin Gray Cassedy was born in Canyon City, Colorado in 1885. Little is found on his education or familial background, though it is known that by 1913 he was living in the Washington, D.C. area. That year he co-founded The Ramblers, a group of landscape painters based in Washington D.C., with Winfield Scott Clime, Charles H. Seaton, and Benson Bond Moore. Their motto, "Nulla Dine Sine Linea", translated to "not a day without a line" and they kept a log of their daily artistic activities. This group soon became the Washington Society of Landscape Painters, which still operates today.

In 1933 Cassedy was hired as an illustrator by the Smithsonian Institution's Bureau of Ethnology, specializing in maps and landscapes. Among the expeditions he was involved in was the archeological dig at the Lindenmeier site, now known as the Soapstone Prairie Natural Area, in Colorado, documenting the artifacts and landscapes of the dig's surroundings. He later worked for the U.S. Department of Agriculture in the same capacity. Among the places he helped to catalogue were parts of rural Mexico, including the Tres Zapotes Mesomaerican archeological dig in the Papaloapan River plain.

Cassedy was a member of the Washington Society of Landscape Painters and the Miniature Painters and Sculptors Society of Washington, D.C. He died in Monterey, Virgina in 1950.

Exhibitions:
1915, 1919: Society of Washington Artists
1925: Society of Independent Artists
1937, 1939: Miniature Poland Springs Art Gallery