She was brought up in suburban Kingswood by her widowed mother – her father having been killed in the First World War – and was educated by the Sisters of Mercy at Angas Street. She then enrolled in the Law School of the University of Adelaide in a very small group of women students, graduated with distinction in 1934 and was admitted to the bar. In 1962 she was the first woman in Australia, and one of the first in the world, to be made a Queen’s Counsel, and in 1965 she was the first woman in Australia to be appointed as a judge of the Supreme Court. In 1971 the state government appointed her to chair its Criminal Law and Penal Methods Reform Committee. This led in 1975 to her giving the Australian Broadcasting Commission’s Boyer Lectures on The Web of Criminal Law. In 1982 she was awarded the equivalent of a knighthood: Dame Commander of the Order of the British Empire. After retirement from the Supreme Court bench in 1983 Dame Roma was appointed chancellor of the University of Adelaide. She was governor of South Australia from 1991 to 1996 – only the second Catholic to hold the post.

Roma Mitchell was a loyal though independent-minded Catholic: that is, like many others, she had difficulties with some teachings and rulings of the church, especially when they involved human relationships. In the 1930s she was involved in the Catholic Guild for Social Studies, a group of young Catholic activists who explored the social implications of Catholic teaching. As a young lawyer in the 1940s she specialised in matrimonial law, which involved divorce cases – an area which some Catholic lawyers refused on principle to handle because the church forbade divorce. In this area, as her biographers observe, she had to balance her faith, her vocation and her developing commitment to justice for women.

For most of her adult life Roma Mitchell was a parishioner of the cathedral. In their biography Roma the First (2007), Susan Magarey and Kerrie Round note that even when travelling overseas Roma never missed Sunday Mass, even if it was hard to find. In the 1960s, in Tokyo she and her travelling companion, unable to find a church near their hotel, took a taxi and ended up at Mass in a shed at the back of a house on the outskirts of the city – much to the confusion of the small congregation of Japanese Catholics. When she was state governor Dame Roma regularly attended Sunday and weekday Mass here, walking down from Government House, and she was given a special seat at the front. When she died in March 2000 she was widely mourned; she had been a very popular governor. Her funeral was one of the largest the cathedral has seen and was televised.