A professor at the University of Toronto, Weinrib is one of Canada’s foremost authorities on constitutional law. Born in Toronto, she is the daughter of Toronto-born parents, Louis Eisenstat (1912–1979), a bookkeeper, and Helen (née Levy) Eisenstat (b. 1918), a homemaker. Weinrib was educated at York University (B.A. in classics summa cum laude, 1970), the University of Toronto (LL.B., 1973), and Yale University (LL.M., 1985).

After becoming a barrister and solicitor, Weinrib was employed as a crown law officer by the Ministry of the Attorney General of Ontario for twelve years, dealing most of that time with constitutional issues. During those years, Canada adopted a new constitution and a Charter of Rights and Freedoms. As a result, constitutional questions were of paramount concern to lawyers, governments, and the general public. Weinrib’s responsibilities as a crown law officer and as deputy director for constitutional law and policy (1987–1988) included liaison between the governments of Ontario and Canada; vetting proposals from all ministries for constitutional validity; arguing constitutional issues before the Supreme Court of Canada; and planning the reorganization of the constitutional work of the Ontario provincial government.

In 1988, Weinrib was appointed to the Faculty of Law at the University of Toronto with a cross appointment to the Department of Political Science. She has been a visiting professor and Fulbright Fellow at the University of Michigan Law School (1993) and a visiting professor at the Hebrew University in Jerusalem (Halbert Exchange Fellow, 1994), the University of the Witwatersrand in Johannesburg (1994), and the Tel Aviv University Faculty of Law (2001). She has served as a consultant to the Israeli judiciary on constitutional issues and studies the impact of Canadian law on Israeli jurisprudence, especially in the areas of constitutional and human rights legislation.

Weinrib publishes, lectures, and consults widely. Her publications include “‘Do Justice to Us!’ Jews and the Constitution of Canada,” in Not Written in Stone, edited by Daniel Elazar, Michael Brown, and Ira Robinson (Ottawa, 2003) and “Hate Promotion in a Free and Democratic Society,” in Hate Speech and the Constitution, edited by S. J. Heyman (New York, 1996). Recent conference presentations range from “The Charter’s [Charter of Rights and Freedoms] Impact: Assessing the First Twenty Years,” the keynote at the 2002 Isaac Pitblado Lectures sponsored by the Law Society of Manitoba, the University of Manitoba, and the Manitoba Bar Association, to “The Canadian Roots of Constitutional Rights Protection in Israel,” at the Jerusalem Conference in Canadian Studies (2002). In addition to consulting in Israel, Weinrib serves on the editorial advisory boards of the University of Alberta Centre for Constitutional Studies and New York University’s journal of comparative constitutional law.

In 1970, Weinrib married Ernest J. Weinrib (b.Toronto, 1943), a professor of law and classics at the University of Toronto. They have three children: Aliza (b. 1977), Sara (b. 1979), and Jacob (b. 1982). Weinrib has three siblings: Marilyn (b. 1945), Barbara (b. 1951), and Sholom (b. 1956) Eisenstat.