Casson was born on May 17, 1898 in Toronto, Ontario. He joined the Group in 1926, and he’s best known for being the youngest member of Group of Seven. He took the “position” when Frank Johnston left the group in 1921.
He did his first public exhibition at the Canadian National Exhibition in 1917.
Along with Carmichael and F.H. Brigden, he founded the Canadian Society of Painters in Water Colour, in 1925.
He left the Group of Seven in 1932. The following year he co-founded the Canadian Group of Painters.
Casson passed away on February 20, 1992, in Toronto, Ontario, at the age of 93.
On May 26, 2008, the PBS “Antiques Roadshow” showcased a painting that claimed, “The painting was given to her grandfather by Casson, his friend and neighbour at the time.” The painting was appraised in the $25,000 to $35,000 range.