Doidge studied classics, political science and philosophy at the University of Toronto before studying for his medical degree. After moving to New York, he studied psychiatry and psychoanalysis at the Columbia University. He served as Head of the Psychotherapy Centre and the Assessment Clinic at the Clarke Institute of Psychiatry (now part of CAMH). He is on the Research Faculty at the Columbia University Center for Psychoanalytic Training and Research as well as working for the University of Toronto’s Department of Psychiatry. He is the author of standards and guidelines for the practice of intensive psychotherapy that are widely used in Canada. In 1993 he presented his early research into this at the White House in Washington, D.C.. Doidge has written several scientific papers on subjects including Schizoid personality disorder, trauma, and Freudian psychoanalysis, including an article he wrote for Maclean's magazine in which he argues that Freud's work is still relevant in modern day psychiatry.

Doidge has written over 170 scientific and popular articles for the New York Times, Newsweek, Time magazine and International Herald Tribune among others, and works as a reviewer for the Harvard Review of Psychiatry. He worked from 1998 to 2001 as a journalist at the National Post before publishing The Brain That Changes Itself in 2008. In it, Doidge demonstrated applications of and evidence for neuroplasticity, including many case studies and examples of recent research in the field. The book did well, generating substantial interest, particularly in the United States and Canada, where it was one of the top ten bestselling science books of 2008. In July 2009, Doidge co-wrote and presented a documentary television program for the Canadian Broadcasting Corporation in which he travelled across North America observing case studies and demonstrating examples of neuroplasticity in The Brain That Changes Itself.

He now appears on radio and television programs and has performed keynote speeches in North America, Europe and Australia.