In 1967, she graduated from the University of Montreal with a Bachelor of Arts and an LL.L. in 1970. She became the Law Clerk for Mr. Justice Louis-Philippe Pigeon of the Supreme Court of Canada in 1971-1972 while completing graduate studies at the Faculty of Law (Civil Section) of the University of Ottawa. She was admitted to the Ontario Bar in 1977.
Ms. Arbour was a Research Officer for the Law Reform Commission of Canada and an Associate Professor and Associate Dean of Osgoode Hall Law School, where she taught from 1974 to 1987. She also was Vice-President of the Canadian Civil Liberties Association until her appointment to the Supreme Court of Ontario (High Court of Justice) in 1987 and to the Court of Appeal for Ontario in 1990.
In 1995, Madam Justice Arbour was appointed as President of a Commission of Inquiry, under the Inquiries Act, for the purpose of investigating and reporting on events at the Prison for Women in Kingston.
In 1996, she was appointed Chief Prosecutor of War Crimes before the International Criminal Tribunal for Rwanda and the former Yugoslavia in The Hague. She has published extensively on criminal procedure, human rights and civil liberties in both English and French.
In 1999 Louise Arbour was appointed to the Supreme Court of Canada.