David Victor Toews was born in 1948 in Winnipeg, one of five children of John Aron and Nettie (Willms) Toews. John and Nettie had both arrived in Canada in 1926 as part of the Russlaender immigration from the Soviet Union. John A. Toews was a prominent Mennonite Brethren churchman and author, and had a lengthy association with Mennonite Brethren Bible College as a teacher and president.
In a 2009 issue of Rhubarb, David recalled of his upbringing, "my mother...told my siblings that my bad, spoiled behaviour was because I was 'artistic'.... and in a family of historians, made room for another kind of narrative, more complex, ambiguous, and real than the official histories that surrounded me and tried to define me." In 1967 David Toews, having completed one year of university in Winnipeg, embarked on an extensive tour including Expo '67 in Montreal, Europe, the Middle East and Southeast Asia. Returning in 1968, he spent a year working in a sawmill in British Columbia before enrolling at Goshen College were he completed a BA in 1971. The same year he married Kathy Waltner and took the name David Waltner-Toews.
Looking for a career that would allow him to work across cultures in a practical and meaninful way, he decided on veterinary medicine and completed his training at the Western College of Veterinary Medicine in 1978. Waltner-Toews practiced as a veterinarian in Alberta and Ontario before pursuing a PhD in Epidemiology at the University of Guelph. Upon completion of his degree, David, Kathy and their two children lived in Indonesia for two years (1985-1987) while David worked on epidemiological projects. He returned to the University of Guelph as a professor in the Department of Population Medicine (1987-2011). During his career he collaborated on numerous ecosystem health research projects in different parts of the world.
Meanwhile, Waltner-Toews pursued writing in a number of genres. His first book of poety as sole author, That Inescapable Animal, was published in 1974. He has also had poems published in many periodicals and anthologies. He has written novels, short stories, and several nonfiction popular science books, in addition to scholarly works in his field. His writing frequently attempts to break down barriers between literature and science. In 2022 he was made an Officer of the Order of Canada for his work in ecosystem health and development.
