Born Orphir, Orkney, the daughter of Isabella Manson and John Graham, weaver and crofter. She was a pupil-teacher in Orphir and then trained as a nurse in Glasgow. She was part of the Women's Foreign Mission, in Old Calabar, Nigeria, and became the first matron of Duketown Hospital. In 1901, she tended Aro casualties after a military campaign was launched against them. She was awarded the Africa General Service medal, with clasps, and in 1906 was appointed a Serving Sister on the Roll of the Order of the Hospital of St John of Jerusalem. Margaret Graham died in 1933 and is buried next to Mary Slessor.