Diane Barwick was born on 29 April 1938 to Beatrice Rosemond, nee O’Flynn, and Ronald Bernard ‘Bear Tracks’ MacEachern. The MacEachern family lived mainly in the remote logging communities of British Columbia, where Diane and her sister Edna were educated by correspondence. From 1947 to 1955 the family lived in Woss Camp on Vancouver Island, where Diane Barwick’s father worked as boss logger and superintendent.

In her undergraduate studies at the University of British Columbia in the late 1950s, Diane Barwick's childhood experiences formed the basis of her first major academic study. Diane Barwick gained a BA (Honours) in Anthropology in 1959. In her Honours essay entitled ‘The Logging Camp as Subculture’ she studied the occupational identification among loggers and their families in the camps of Vancouver Island, including Woss Camp. Her Honours essay was based upon five months' fieldwork in six logging camps in Englewood Valley. Diane Barwick was later to draw parallels between the remote, close knit logging communities she researched in British Columbia, and those of the Aboriginal communities she investigated in Victoria, Australia.

As of April 1959, Diane Barwick had worked for several years at the University of British Columbia Anthropology Museum as Audrey Hawthorn's student assistant, with Thora Hawkey. She spent the summer of 1959 working at The Quest for Handcrafts in Banff and Victoria in Canada. From October 1959, Diane worked for nine months with Wilson Duff at the Provincial Museum of British Columbia, a time when the Museum was under the directorship of Clifford Carl. She specialised in the museum's Northwest Coast Indian collection. During return visits to North America in the years through to 1965, she periodically held other curatorial positions at this and other museums.

In 1959 Diane Barwick was contacted by Professor John Barnes about a proposed project about people of part-Aboriginal descent in Victoria, Australia. She responded with enthusiasm, and in October 1960 she arrived in Australia, having been awarded a postgraduate scholarship by the Australian National University. She subsequently spent 14 months engaged in fieldwork among the Aboriginal people of the Goulburn Valley, where she worked in a fruit cannery, and in Melbourne suburbs including Fitzroy, Collingwood and Northcote. Her research took her into Aboriginal households and also into the offices of the Aboriginal Welfare Board, Aborigines Advancement League, Brotherhood of St Laurence, and other government, welfare and rights organisations which had contact with the Aboriginal community.

Diane Barwick’s studies of contemporary Aboriginal community networks led her to begin collecting the genealogies of Aboriginal Victorians. Among her informants was Philip Eric Felton, Superintendent of the newly formed Aboriginal Welfare Board – Victoria, who was also undertaking such work. Diane Barwick’s genealogies incorporated the genealogies collected by Philip Felton, Norman Tindale, and others. Her genealogies are inclusive and broad-ranging, and reflect the life histories of Aboriginal people as well as the demographic and administrative patterns in the Aboriginal history of Victoria. Diane Barwick continued collecting data into the 1970s and to a lessor extent also thereafter, periodically spending intensive periods of time on this work.

In 1966 Diane Barwick found a new historical source which shaped the direction of her subsequent research, including her Collected Genealogies. That year the archives of the Board for the Protection of the Aborigines - Victoria were rediscovered in the Old Treasury building in Melbourne. With Philip Felton's help, Diane Barwick researched these records between 1966 and 1972, transporting batches of records home to Canberra from Melbourne and taking detailed notes before returning them to collect another batch. She also consulted archival, newspaper and oral history sources in this time. During this period she was a Research Fellow in the Department of Anthropology and Sociology at Australian National University.

Diane Barwick's first job after submitting her PhD was as the first resident executive officer for the Australian Institute of Aboriginal Studies, on Lonsdale Street, Melbourne.

After completing her PhD, Diane Barwick lived and worked for the rest of her life in Canberra. She wrote widely and presented countless conference papers on topics in historical and political anthropology, including clan boundaries among the Kulin nations of Victoria, smallpox, Victorian Aboriginal demography, and the changing role of Aboriginal women. In an obituary for Diane Barwick published in the Australian National University Reporter, colleague and friend Diane Bell notes that Diane Barwick worked tirelessly to ensure the recognition and success of the sub-discipline of Aboriginal history that was emerging at this time. As founding editor of the journal of Aboriginal History from 1977 until 1982, and in her involvement with the journal thereafter, she set a standard for Australian ethnohistory that was both scholarly and accessible to a wide audience.

The institution with which Diane Barwick was chiefly affiliated was the Australian Institute of Aboriginal Studies, Canberra. Diane Barwick held many roles at the Australian Institute of Aboriginal Studies from the time of its establishment in 1961. She was a foundation member, and the first woman to be elected to its council, in May 1978. She was member and chairperson of the Social Anthropology Committee and Publications Committee, and she also instigated the History Committee. At the time of her death in 1986 she was employed at the Australian Institute of Aboriginal Studies as research officer on the Aboriginal Biographical Project.

Throughout her career, Diane Barwick fostered Aboriginal initiatives in research, scholarship, education and leadership. For example, with Margaret Valadian in 1971 she was academic co-director of a six week workshop designed to foster Aboriginal leadership, entitled ‘The Culture, Identity and Future of the Aborigines’, held at the Centre for Continuing Education at the Australian National University, Canberra. She was an invited member of the Aboriginal Treaty Committee from 1980-82, and she also contributed a historical report on the Framlingham Land Claim in Victoria which helped secure the land at Framlingham for its Indigenous owners.

Despite her energy for and commitment to her chosen field, and although she applied for numerous academic posts at the Australian National University, Diane Barwick never gained permanent employment as an academic. She was employed in temporary positions as a lecturer and a tutor at the Australian National University at periodic intervals between 1974 and 1982, and she was an active member of Canberra’s academic community until her death.

Diane and her husband, zoologist Richard Barwick, had one child, a daughter named Laura. Following Laura's birth, Diane Barwick’s anthropological imagination found a new outlet in her maternal role. Unused to long periods alone at home, Diane Barwick took around-the-clock notation of Laura’s development during her first two years.

Richard Barwick actively supported Diane Barwick’s work as an anthropologist, and they both offered moral and practical support to the many people and groups engaged in initiatives for Aboriginal rights in the 1960s and 1970s. Diane Barwick was known for her intellectual rigour, compassion, and loyalty, and her unstinting commitment to the fields of historical and political anthropology and to Aboriginal equality and justice.

Diane Barwick's family included her sister and brother-in-law Edna and Harvey Borden, and their son Ian.

Diane Barwick died of a cerebral haemorrhage while working at her desk at the Australian Institute of Aboriginal Studies on 4 April 1986. She is buried at Gungahlin cemetery.