Australian-born. After studying at Melbourne Grammar School, he moved to London in 1905. Before, he briefly stayed in Paris. When in London, he studied at Slade School of Fine Art and when still student there, he was asked to join the team and teach. He stayed there for ten years.
He exhibited in the Goupil Galleries, the Chenil Gallery in Chelsea and with the Friday Club (he was one of the founding members of Vanessa Bell’ Friday Club). He was also a member of New English Art Club from 1911. In 1913 he exhibited in Armory Show in New York. His early pencil drawings created at Slate School of Fine Art are held in UCL Art Museum.
He was a friend with Augustus John and also together with James Dickson Innes painted in North Wales between 1910-1913. In 1914, he and Augustus John painted in Collioure in France. Further, he returned to southern France for painting trips three times before the World War I.
He married his model-muse, Edith Harriet Price (1890-1984) in 1913. Under her model pseudonym ‘Lyndra’ she was one of Lees and Augustus John’s principal pre-WWI models.
Driven by poverty and mental health problems, he was confined to asylums; first in 1918, then permanently from 1919 until his death in 1931 at West Park Hospital, Epsom.