Although not a prolific worker or exhibitor, he is regarded as one of the finest of English landscape watercolourists. He was made a Chevalier of the Legion of Honour in recognition of a painting sent to the Paris International Exhibition of 1878. Collier was industrious, retiring and often in poor health, yet financially independent, able to work without pandering to popular taste and to travel at will into the Suffolk countryside. In 1879 he arranged for the construction of a large house and studio at 9 Hampstead Hill Gardens in Hampstead where he spent his days painting and entertaining artist friends.