Dr Kathy Cornack was raised in Brisbane, Australia. She developed an early love for animals and decided on veterinary medicine as a career, just ahead of being a midwife or forensic scientist. She earned her veterinary degree from the University of Queensland in 1985. After graduation, she worked for the Australian government helping cattle and sheep graziers in the Queensland outback. Following that, she did locum small animal work in Australia and the UK. She then earned a master's degree in ruminant nutrition while continuing to work in small animal practice.

Dr Cornack ran her own mixed animal practice in a rural area for a few years, during which time she became IVAS certified in acupuncture. Afterwards, she did more locums in small animal practice around Australia and completed membership exams in veterinary behaviour.

She and her family spent four years living in the Seattle, Washington area, during which time she taught natural health classes at a community college and in natural animal health stores, worked as a technician in an integrative veterinary practice, and as a birth doula. Returning to Australia, Dr Cornack purchased a small animal practice, then moved to Newcastle, New South Wales and formed her current practice, Holistic Vets Newcastle.