Kim Ondaatje was born Betty Jane Kimbark on October 2, 1928, in Toronto, Ontario. She grew up in Toronto and studied painting under the Canadian artist Yvonne McKague Housser and, in 1947, enrolled at the Ontario College of Art. In 1948 she began studies in the Fine Art program at McGill University, but later dropped out and chose to study English Literature, receiving an MA at McGill in 1954 while on a teaching fellowship.

Committing herself to painting full-time by the early 1960s, Ondaatje later became an award-winning printmaker, directed two art films and three documentaries, and published three books of photography. Alongside artists Jack Chambers and Tony Urquhart, Ondaatje co-founded and helped to develop Canadian Artists Representation (now CARFAC) in London in 1968 — one of the first artists’ unions of its kind anywhere. She has taught in the arts throughout her career, working for the London Public Gallery, the Agnes Etherington Art Centre, the Art Gallery of Ontario, and for the outreach program of the Emily Carr College of Art in British Columbia and the Yukon. With many exhibitions of her paintings and prints in Canada and abroad, she has received national and international recognition. Ondaatje’s work is situated in a history of Canadian art after the internationalist nonobjective work of the Automatistes, the Regina Five, and Painters Eleven. She was married to the poet D.G. Jones, and later was married to the writer Michael Ondaatje. She has six children. Awareness and respect for the environment have long been integral to Ondaatje’s art and life. In a 1973 interview with art historian Lora Senechal Carney, she reflected on her experience painting her large industrial landscapes (the Factory Series): “Factories were threatening but very fascinating … it was a very complex kind of experience. Anyone is concerned today, and as a mother of six children I’m very concerned about what’s happening to the environment.”

In 2009 Ondaatje received the Governor General’s Award in Visual and Media Arts. Her work has also been the subject of major retrospectives, including the University of Toronto Art Centre’s Kim Ondaatje: Paintings 1950-1975 (2008), and Kim Ondaatje Museum London (2013), as well as comprehensive exhibitions at The Robert McGlaughlin Gallery (2014) and the Agnes Etherington Art Centre (2015). Curator Bruce Mau chose Ondaatje’s print Inco Slag Train for the 2018 Toronto exhibition Awakening, describing it as “very beautiful … a challenging image.” Ondaatje’s paintings and prints can be found in numerous collections, including The National Gallery of Canada, the Art Gallery of Ontario, the Montreal Museum of Fine Art, and The Robert McGlaughlin Gallery, among many others. In July 2018 her painting Hearn Plant, Toronto Harbour was chosen by curators Georgiana Uhlyarik and Wanda Nanibush to be included in the Art Gallery of Ontario’s J.S. McLean Centre for Indigenous and Canadian Art. In 2021, The Art Gallery of Ontario held a major exhibition entitled Kim Ondaatje: The House on Piccadilly Street which focused on Ondaatje’s paintings and prints from the late 60s and early 70s. Her painting Blue Bedroom also featured prominently in the Montreal Museum of Fine Art’s exhibition Views of Within in 2023. Ondaatje has, for the past fifty years, lived near Verona, Ontario.