Her father, James MacDonald Troup, was a doctor and later advisor to Jan Smuts; her mother was Alberta, née Davis.
[1] In 1938 and 1939 she was in private practice in South Africa, but returned to England at the start of the Second World War.
From 1946 to 1951 she worked as a designer for Cockade Ltd., and in 1952 took up a post as senior tutor at the Royal College of Art, where her husband Hugh was a professor.
[3] Late in life, Margaret Casson experimented with what she called shadow drawings or "sciagrams", photographs made either with or without a camera; some were platinum–palladium prints.
[2][4][5] Margaret Casson died in London on 12 November 1999, less than three months after the death of her husband.