Born in Great Yarmoth, Joy was the elder of the two brothers William and John Cantiloe Joy. Both brothers were marine artists of considerable merit, who enjoyed a close relationship throughout their lives resulting in many paintings which were jointly executed. They both worked in watercolour, John almost exclusively, but William also painted in oils, which are comparatively rare. William's work was in general finely painted, highly detailed in the treatment of the figures, boats and their riggings, and equal to many of the Dutch 17th century Masters and to the quality of English painters such as Charles Brooking (1723-1759) and Joseph Stannard (1797-1830).
Joy exhibited at the Royal Academy in 1825 and 1832, at the British Institution in 1823 and 1845, and latterly from an address in Chichester, where he died.