Colin Johnston


Colin* is a strategic thinker. That’s good for his clients, who he represents in litigation matters relating to public and administrative law, professional regulation and health law. Colin appears in all levels of court in Ontario and before various administrative tribunals. Colin brings§ a diverse range of experience to his practice. Having served as a prosecutor at the College of Physicians and Surgeons of Ontario gives him an inside understanding of professional regulation. Colin also leads medical ethics seminars for MD students at the University of Toronto and was a member of the research ethics board for three Toronto teaching hospitals. His experience gives clients perspective on complex legal challenges. When professionals face multiple obstacles and significant stress, Colin helps his clients see past their immediate difficulties and brings a long-term view, working to develop a strategy to protect clients’ personal and professional interests. .



Colin Johnston

is counsel at Lenczner Slaght.

Colin's litigation practice focuses on public and administrative law, with a particular emphasis on professional regulation.  He has appeared as counsel before all levels of court in Ontario and in hearings before various administrative tribunals. Colin has considerable experience in the regulation of health professionals.

From 2009 to 2014, Colin was counsel to the College of Physicians and Surgeons of Ontario, where he appeared in numerous hearings before the College’s Discipline and Fitness to Practise Committees. He previously practised litigation at a large national law firm in Toronto, representing clients in complex commercial and regulatory disputes.

Colin recently returned to Toronto from the United Kingdom, where he pursued graduate studies in law at University College London.

  • Canadian Bar Association

  • Ontario Bar Association

  • The Advocates' Society

  • Rohringer v. RCDSO: revisiting the test for interim orders against health professionals

    Effective May 30, 2017, professional regulators under the Regulated Health Professions Act received a new power to temporarily restrict or suspend the licence of a health professional during the course of an investigation into allegations of misconduct or incompetence.  Previously, regulators could impose such measures only after the conclusion of an investigation and commencement of a Discipline Committee proceeding. This raises the question, what is the appropriate threshold of risk that must be established in order to suspend or restrict the licence of a professional whose case is still under investigation? What evidence is required? What reasons must be given in order to justify such an order? These questions are considered in the recent decision of Rohringer v Royal College of Dental Surgeons of Ontario 2017 ONSC 6656.

    Colin Johnston | March 27, 2018

  • Best Lawyers (2019)

    Health Care Law

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