Janette Deacon was born in Cape Town in 1939. She became interested in Archaeology when she registered for a BA course taught by Professor A J H Goodwin at the University of Cape Town in 1958.
After Goodwin died in 1959, Ray Inskeep was appointed in his place in 1960 and encouraged his students, amongst them Carmel Schrire, Garth Sampson and Janette Buckland, to participate in field work and to visit rock art sites in the Cederberg with Ginger Townley Johnson, Percy Sieff and Hym Rabinowitz.
After graduating in 1960, Janette worked as a research assistant to Professor W J Talbot in the Department of Geography at UCT in 1961, and in 1962 she was appointed as Junior Lecturer in the Department of Archaeology. During that year she met Hilary John Deacon who had returned to UCT after 6 years as a field geologist to do an Honours degree in Archaeology. They married in December 1962 and moved to Grahamstown where Hilary was appointed as the Archaeologist at the Albany Museum. Hilary's field projects between 1963 and 1971 provided the data for his MA and PhD theses and for Janette's MA.
When Hilary was appointed as Head of the new Department of Archaeology at the University of Stellenbosch in 1971, they moved back to the Western Cape. From 1972 to 1975, Janette was appointed as a temporary lecturer in the UCT Department of Archaeology, and between 1976 and 1988 she worked as a researcher for various projects at the University of Stellenbosch.
Her PhD, awarded in 1982, analysed Later Stone Age assemblages dating to the last 20 000 years from Nelson Bay Cave, Boomplaas Cave and Kangkara shelter, correlating the scale and timing of changes in stone artefact traditions with changes in various environmental parameters. She edited the South African Archaeological Bulletin from 1976 to 1993. In 1989, when Jalmar Rudner retired as Archaeologist at the National Monuments Council, Janette was appointed in his place and worked there until she retired at the end of 1999.
Since 1998, she has arranged a series of courses and workshops on rock art site management, or has given advice, for the Southern African Rock Art Project in South Africa, Botswana, Namibia, Zimbabwe, Zambia, Malawi and Tanzania aimed at identifying rock art sites for nomination to the world heritage list and training the site managers. Since 2005, she has managed the South African Rock Art Initiative, a programme of the Getty Conservation Institute, that has trained rock art tourist guides and rock art site managers at the Mapungubwe World Heritage Site and the Cederberg.