Rosemary Kilbourn was born in Toronto in 1931. She graduated from the Ontario College of Art in 1953, at which time she received a medal for drawing and painting. Shortly after graduation she emigrated to London, England, where she worked and studied until 1956.

Over the years, Rosemary Kilbourn has been active as a teacher, a wood engraver and a stained-glass artist. As an engraver she has created illustrations for a number of books. Among these are The Firebrand by her brother William Kilbourn, published in 1956 by Clarke, Irwin. She also produced wood engravings for the 1958 edition of Farley Mowat's The Desperate People (Little, Brown), for William Kilbourn's History of the Steel Company of Canada entitled The Elements Combined (Clarke, Irwin, 1960) and for The Shadow of the Year (Aliquando,1976) by Florence Wyle. One of Kilbourn's most well-known engravings, based on an interpretation of The Fruits of the Earth by Frederick Philip Grove, was featured on a 17-cent Canadian memorial author's stamp in 1979.

Kilbourn's engravings first appeared in the Canadian Society of Graphic Art annual exhibitions in 1958, and then again in 1962, 1964 and 1967. They were included in a show called 'Prints and Drawings' at the National Gallery of Canada in Ottawa in 1966, and were exhibited there again in 1969 in a show entitled 'How Prints are Made'. Her engravings on religious themes were displayed at Regis College, Toronto between 1963 and 1966. Rosemary exhibited with the British Society of Relief Block Printers from 1973 to 1975, and participated in the Canadian Biennial of Prints and Drawings (1978). In addition, Kilbourn exhibited her wood engravings from 1959 to 1987 in various group and solo shows at McMaster University, at the Sisler Gallery (Toronto), the Lewis Library in Deep River, the Brampton Library and Art Gallery, the Alice Peck Gallery in Burlington and the Grimsby Art Gallery. She exhibited with the Society of Wood Engravers (England) from the late 1990s, and was awarded membership in the Society in 2001. Her engravings are found in major museums and galleries across the country. These include the Montreal Museum of Fine Art, the Waterloo Art Gallery and the Art Gallery of Greater Victoria, BC. Her engravings are also represented at McMaster University, the University of Guelph and the Universities of Regina and Calgary. Rosemary Kilbourn was elected to the Royal Canadian Academy of Arts in 1977. She continues her long-term residence in The Dingle School, a nineteenth-century schoolhouse ensconced in a protected forest on the Niagara Escarpment north of Toronto.