Lesli has been a lawyer in Ontario since 1992. She began her career working for several years at a Toronto litigation firm, then left to start her own practice in animal rights law.
For ten years Lesli acted for individuals and organisations in a variety of animal-related cases in the only practice of its kind in Canada. She spent many of those years in litigation against the Federal Government regarding the right of non-governmental observers to document the annual seal hunt on Canada’s east coast.
Lesli has lectured widely at universities and law schools across Canada and in the United States. For several years, she has been an adjunct professor at the University of Toronto’s faculty of law where she instructs a course on animals and the law. She has been a frequent commentator in print, radio and television media on the subject, and she is the author of Animals and the Law, the first Canadian law text on the subject, published in December 2011 by Irwin Law.
In recent years, Lesli’s full-time work has been in the human rights and poverty law fields, and she is currently the Barrister at Legal Aid Ontario’s Clinic Resource Office.
Along with Clayton Ruby, one of Canada's best known and respected criminal lawyers, Lesli was co-counsel to an NGO and two individuals who legally challenged the Federal Government's efforts to control access to the seal hunt. The case was a constitutional challenge, based on freedom of expression, that lasted for almost seven years. An inherent conflict was, and remains, the fact that the same Federal Government promotes the hunt, purports to regulate and govern the hunt, and exercises control over critical observers.
Lesli was the keynote speaker for the 2012 Animal Law Lecture Series.