James Cassie was born at Keithhall near Inverurie, Aberdeenshire, the son of a prosperous tea and spirit merchant. Although briefly a pupil of the artist James Giles, Cassie was largely self-taught. He began his career as a painter of animals and portraits, but on moving to Aberdeen he increasingly turned his attention to local seascapes and coastal scenes, especially at dawn and sunset. He favoured these outdoor scenes, but continued to paint some domestic subjects and portraits throughout his life. In 1869 he moved to Edinburgh and was elected an associate of the Royal Scottish Academy. Shortly before his death in 1879 he was elected an Academician.