John Kasyn was known for his paintings of city life, particularly his images of old Toronto homes. His work displayed artistic merit and provided nostalgic documentation of the historic buildings of Toronto. Often depicting the back lanes and rear views of working class Toronto semi-detached houses, Kasyn stated that the backs of homes were where the occupants revealed their true selves, and that the house fronts were reserved for display. Kaysn was more interested in such details as the broken fences and clotheslines that he felt gave insight into the lives of the occupants.
Kaysn was born in Poland, but moved to Winnipeg in 1938, and in 1940, he and his family moved to Toronto. Kasyn began his artistic education at the Winnipeg Museum while still in public school. He studied at the Ontario College of Art under Jock MacDonald, F.S. Challener, George Pepper and R.W. Murphy. Upon graduation he became the Art Director at the Design Studio before turning to painting full time.
In 1966, Kaysn was awarded the Gold Medal at the Annual Exhibition of the Canadian Society of Painters in Water Colour. He is represented in numerous public and private collections in both Canada and the United States, and he held solo shows at Wallack Galleries, Ottawa, DeVooght Gallery, Vancouver, and Kaspar Gallery, Toronto, among others.