Margaret Gray was born in Sydney in 1875. She trained at the Coast Hospital in Sydney (later known as Prince Henry Hospital), and worked as Matron of the Dongrayald Hospital in Lismore before going to England at the outbreak of war in 1914, and offering her services. After working at Brighton Hosptial in England with mainly Indian Army casualties, she was sent to France and worked in the British Red Cross Hospital in Rouen, with both British and Australian patients. She stayed there until the end of the war. Gray was awarded with the Royal Red Cross for her work.

In 1920 Gray was appointed matron of Graythwaite Convalescent Hospital, North Sydney, and later matron at Cavell House, the rest home for trained nurses. Margaret Gray occupied this position until her death on 16 January 1933.