Born in England, Cosmos J. Shurly was brought to the U.S. by his parents, jeweler John Martin Shurly and Elizabeth Catherine Chumley, in the late 1830s. He appears to have spent most of his childhood and young adulthood in Rochester, NY, where he went into the business of the J.C. Flint Co., a prominent American saw manufacturer. He married one of Flint's daughters, Elizabeth Flint.
In 1873, Shurly and a partner, Jerome Dietrich, set up their own saw factory in Galt (now Cambridge), Ontario. Thanks to high quality and a number of innovations introduced by Dietrick, the Shurly-Dietrich brand of Maple Leaf brand saws became enormously successful, and may have been the first brand to use the maple leaf as a symbol of Canada.
In 1910, Shurly sold out his interest in the company to his partner, and retired to private life, except for involvement in the Galt Hospital Board and the Galt Country Club.
He and his wife had three sons and a daughter: Ray C. Shurly, Fred Theodore Shurly, Montague C. Shurly, and Mrs. R. H. Dickson.
His brother Robert V. Shurley was a midwestern newspaper publisher and editor. Sibling Edmund Richard Pitman Shurly fought in the 26th New York Volunteers, was wounded at Fredericksburg, and served in Wyoming and Montana for several years after the Civil War, helping build forts and guard wagon trains on the Bozeman Trail. Another brother, Ernest Lorenzo Shurly, became a prominent Detroit physician.