Rosalind Mary Wrong was born on 11 April 1919. She was the eldest daughter of the Oxford mathematician Edward Murray Wrong (1889-1928) and Rosalind Grace Wrong (Smith) (1892-1983), and grand-daughter of the Canadian historian George M. Wrong (1860-1948). She was educated at Dragon School, Oxford, 1926-1931, St. Paul's Girls School, Hammersmith, 1931-1932, and at Channing School, Highgate, 1934-1938. She then studied Mathematics and Modern History at Lady Margaret Hall, Oxford, 1938-1942. After her own university studies, she became an Assistant Lecturer at Manchester University in 1943, and then Tutor at Lady Margaret Hall in 1946. Part-time tutoring at Cambridge's Pembroke and Girton Colleges followed, then in June 1947 Rosalind Mary Wrong married the scientist John Murdoch Mitchison, son of novelist and poet Naomi M. Mitchison (1897-1999). In 1953, the couple moved to Edinburgh with their growing family. J. Murdoch Mitchison was appointed Professor of Zoology, Edinburgh University, in 1963.

Shortly after the move, Rosalind Mary Mitchison became an Assistant at the History Department, Edinburgh University in 1954, and then from 1958 she was a part-time Assistant at Economic History. From 1959 she did part-time work for the History of Parliament Trust, and then from 1962 she taught at the Scottish History Department, Glasgow University. In 1966 Mitchison was teaching part-time at Edinburgh University again, and then in 1967 she became a Lecturer in Economic History, then Reader in 1976. One of her students had been the politician, Gordon Brown. In 1981, Mitchison was appointed Professor of Social History at the University.

Mitchison's publications spanned seven decades from the 1940s to 2001, and include:Agricultural Sir John(1962);A history of Scotland(1970);Life in Scotland(1978);Lordship to patronage: Scotland 1603-1745(1983);Why Scottish history matters(1990); and,The old poor law in Scotland(2000).

Mitchison officially retired in 1986 but continued to research, teach, write and publish, holding a Leverhulme Emeritus Fellowship until 1988. Rosalind Mary Mitchison died in Edinburgh on 20 September 2002, and she was cremated on 30 September 2002.

Mitchison had been described as 'the 20th century's foremost exponent of the social history of Scotland' (The Daily Telegraph, 24 September 2002), and by Tam Dalyell as 'a pioneering social historian' (The Independent21 October 2002).