Marie Olive Reay was born in Maitland, New South Wales on 1 July 1922.
Reay began her career in anthropology at the University of Sydney, where for her MA she undertook fieldwork among Aboriginal communities in western New South Wales (Walgett, Bourke, Moree, Coonabarabran, and other locations) in the mid-to-late 1940s. Marie Reay spent four years working with Aboriginal communities in New South Wales, usually spending about six months in each community, After completing her MA, she worked as a research assistant at the London School of Economics.
Upon returning to Australia in 1950, Reay was appointed as a lecturer at the Australian School of Public Administration (ASOPA), which provided her the opportunity for her first fieldwork in Papua New Guinea. She intended to study the changes that had taken place among the Orokaiva since they had last been studied by F. E. Williams. However, her research was cut short by the eruption of, as she put it "Mount Lamington, an allegedly extinct volcano." The eruption caused massive devastation and Reay, along with other surviving Europeans, was evacuated from the area. Her niece, Heather Turner, remembered that Marie Reay's recollections of the eruption had been quite traumatic, and made a deep impression on her.
In 1953, Marie Reay won a scholarship to study at the then Research School of Pacific Studies (now Pacific and Asian Studies) at the Australian National University as a doctoral student under the tutelage of S. F. Nadel and W. E. Stanner in the Department of Anthropology and Sociology. She intended to return to her uncompleted work among the Orokaiva, however was instead encouraged by Nadel to go to the Highlands and "provide him with data for classifying and explaining the varieties of social structure" (Ethnographic Presents, p.138). In 1953 she arrived at Minj in the Highlands and began her groundbreaking work on the Kuma. Reay was the first female anthropologist in the region, and managed to install herself among the Kuma despite the disapproval of the local district officer, who had very particular views on "the British Empire" and "white prestige" (Ethnographic Presents, pp.141; 151) and who she scandalised by wearing shorts.
In her own recollections, Marie Reay stated, "My fifteen months with the Kuma changed my life" (Ethnographic Presents, p.157). However, she found difficulties in her return to Canberra. She soon found that the topics she intended to focus on in her PhD work were "not acceptable to my supervisor" and she "floundered in the search of a more acceptable topic" while attempting to avoid the trap of being a female anthropologist who would "fill a gap in men's studies" by writing about the women (Ethnographic Presents, p.157-158). Reay submitted her PhD work in 1957, which was published as The Kuma: Freedom and Conformity in the New Guinea Highlands in 1959.
Shortly after completing her PhD, Reay was appointed as a research fellow in the Research School of Pacific Studies at the Australian National University, where she remained until her retirement in 1988, after being promoted to Fellow and Senior Fellow. For a few years, Reay returned to her original study of Aboriginal communities in Australia, this time in Borroloola in the Northern Territory. However, after publishing some articles, she abandoned the project and returned to the research that had changed her life.
Marie Reay continued to do fieldwork in Highlands region of Papua New Guinea throughout her life, maintaining a home at Minj. Reay studied many changes in Papua New Guinea, especially in religion, social structures, politics and elections. Marie Reay was in Papua New Guinea so often that a colleague dubbed her "Our Lady of Perpetual Fieldwork." She died in Booragul, NSW on 16 September 2004. In 2011, her papers were donated to the ANU Archives, where they were discovered by Francesca Merlan, including a nearly complete manuscript, Wives and Wanderers, which she edited and brought to publication in 2014. Reay's work, had it appeared earlier, "would have had a central place in anthropological literature on Papua New Guinean societies, especially those of the Central Highlands... the foundational, indeed the first, book on women's lives in that part of the world" (Wives and Wanderers, p.1). With the publication of Wives and Wanderers, in many ways still a very important text on the condition of women in the Central Highlands even many years after the original studies, there was renewed interest in Marie Reay's research and legacy. In 2019, the ANU opened the new Marie Reay Teaching Centre in the Kambri development, in honor of her important contributions to anthropology at ANU.