Dr Russ Harris, M.B.B.S., is a physician and psychotherapist, working in private practice in Melbourne, Australia. He was born in England in 1966, and graduated in medicine from the University of Newcastle-Upon-Tyne, in 1989. He emigrated to Australia in 1991, where he began working as a GP. He became increasingly interested in the psychological aspects of health and wellbeing, and this interest led to a career change - from medical practitioner to therapist.

Since 2005, Russ has provided training in ACT (Acceptance and Commitment Therapy) for over 80,000 health professionals around the globe. He has authored four ACT textbooks, and six ACT-based self-help books. His best-known book, The Happiness Trap, has sold over one million copies worldwide, with translations into over thirty languages. In 2015 Russ created an ACT protocol for the WHO (World Health Organization), for use in refugee camps. The WHO have now researched and published three trials based on this protocol, showing that it not only significantly reduces depression and PTSD but also prevents the onset of mental health disorders in those at high risk. Russ also wrote and designed a cartoon-based book for the WHO (based on ACT) called Doing What Matters In Times of Stress - and this is now the most commonly downloaded mental health resource on the WHO website.