[4] The CCLA was founded in 1964 in Toronto, prompted by the Ontario government's proposal of a bill that would have granted special powers to the police in the face of a rise in organized crime.

The ACL was led by Irving Himel, and in response to the bill, he gathered human rights leaders in Toronto, including Pierre Berton, June Callwood, Bora Laskin, Mark MacGuigan, Harry Arthurs, and John Keiller MacKay, and they formed the CCLA with Mackay as its honorary president.

[4] In 1968, the CCLA won a grant from the Ford Foundation to study due process in Canadian lower courts and used the findings as a guide for its advocacy in the ensuing years.

[4] In the opinion of Dominique Clément, its most enduring contribution in the 20th century was its influence on the drafting of the 1982 Canadian Charter of Rights and Freedoms.

Alan Borovoy served as general counsel of the organization from 1968 to 2009 and under his leadership, he and the CCLA became famous throughout Canada as defenders of free speech and civil liberties.