Born in London, the son of a Presbyterian minister, he was brought up in Plymouth and served with the Argyll and Sutherland Highlanders during the first world war. He read medicine at Edinburgh University and qualified in 1920. In 1927 Grierson was appointed to the new post of surgeon specialist at the Public Hospital, Georgetown, British Guiana. He made a great success of his work there; Grierson revolutionised surgery in the colony, and was extremely popular with people of many races for his cheerful disposition and sense of humour. He had no time for red tape or inefficiency. Owing to ill health he retired in 1949 to Cornwall and later to Bath, where he died 23 February 1961 at the age of 62, survived by his widow and three children.