Paul-André Crépeau was born 20 May 1926 in Gravelbourg, Saskatchewan, son of a French-American lawyer and his mother was a Québecoise schoolteacher. Crépeau and his wife, Nicole Thomas, had three children. He died in Montreal, 7 July 2011.

Crépeau first pursued his education in Canada. He obtained his Licence in Philosophy at the University of Ottawa (1947), then a B.C.L. at the Université de Montréal (1950). Upon receiving a Rhodes Scholarship, he obtained a Bachelor's of Civil Law at Oxford (1952). Following that, he completed a doctorate (1955) at the Faculty of Law at the Université de Paris, where he wrote his doctoral thesis on medical law (La responsabilité civile du médecin et de l’établissement hospitalier, published in 1965). His thesis won the Prix Robert-Dennery. Crépeau finished his training at the International Faculty for the Teaching of Comparative Law in Strasbourg, where he earned an additional diploma in Comparative Law (1958).

Crépeau began his career as a professor in 1955 at the Faculty of Law of the Université de Montréal. In 1959, he joined the Faculty of Law at McGill University, where he taught law for more than 50 years. His contributions to the study and development of Canadian civil law were numerous and varied. He played a central role in the reform of the Civil Code of Québec and the creation of the Quebec Charter of Human Rights and Freedoms.

In 1965, he was tasked with updating the Civil Code of Quèbec to reflect contemporary realities and values. As president of the Civil Code Revision Office, he worked for 12 years with close to 150 jurists on the recodification. His draft for an updated Civil Code was presented to the Quebec National Assembly and became the framework for the new Civil Code of Quebec in 1991. In collaboration with McGill professor Frank. R. Scott, Crépeau presented a report in 1971 on a legal framework concerning human rights and freedoms. This project served as the basis of the Quebec Charter of Human Rights and Freedoms. As an internationally-recognized expert in the area of civil law, Crépeau became involved in the work of the International Institute for the Unification of Private Law (UNIDROIT; Institut International pour l'Unification du droit privé). He directed an international project to codify contract law in international commerce. The creation of the Paul-André Crépeau Prize in 2001 was in acknowledgment for his contributions to international commercial law.

He spent a large part of his career studying the judicial systems of other countries. His participation in the work of the International Academy of Comparative Law, which he headed from 1990 to 1998, shows his interest in comparative methods. Holder of the Arnold Wainwright Chair in Civil Law from 1976 and Director of the Institute of Comparative Law from 1975 to 1984, he founded the Quebec Research Centre of Private and Comparative Law at McGill University in 1976. His contributions to the field of law also include l'Édition historique et critique du Code civil du Bas Canada/Historical and Critical Edition of the Civil Code of Lower Canada 1866-1993, Traité de droit civil and a Dictionnaire de droit privé et Lexiques bilingues/Private Law Dictionary and Bilingual Lexicons. The jurist assumed numerous responsibilities as an expert consultant to other lawyers and on questions relating to his specialisation.

In addition to receiving six honorable doctorates, Paul-André Crépeau has been awarded with numerous prizes highlighting his contribution to the advancement of civil law in Quebec and elsewhere, notably the Order of Canada (1992), the National Order of Quebec (2000), the Ordre national du Mérite (France, 1984), and the Ordre national des Arts et Lettres (France, 2004).