Lees was born in Hobart, Australia, moving to London in 1905. He was a friend of Augustus John and James Dickson Innes, working with them in Wales and at Collioure in France. He was the only Australian artist represented at the 1913 Armory Show in New York, the first large scale exhibition of modern art in America.

Lees married Edith, known as Lyndra, in 1913. She had been a frequent model of Augustus John’s.