William Cox was a member of the Hammersmith Amateur Wrestling Club, and alongside his younger brother, John, was one of 14 club members to compete in the wrestling events at the 1908 Olympic Games. Competing in the bantamweight freestyle event, he lost his sole match to Frederick Tomkins of the Olympic Amateur Wrestling Club in Walworth. Cox grew up in Chelsea, London, one of 12 children born to Hannah Cissell and John Edward Cox, a baker/confectioner. William Cox worked as a salesman by career, and ran a wallpaper store in 1939. He died at the age of 90 in early 1975.