Born and raised in Alberta, Pincher Creek, McLachlin grew up with the German fundamentalist Christian values of hard work and moral uprightness. She excelled in her studies at the University of Albert winning the award as the top student in her graduating class. She was called to the bar in 1969 and eventually practised law in British Columbia where she eventually became a Chief Justice in the BC Supreme Court.
PM Jean Chretien appointed her a Canadian Supreme court justice in 2000, the office in which she served until she retired in 2017.
She clashed with PM Stephen Harper and justice minister Peter MacKay in support of the appointment of Marc Nadon to the Quebec Supreme Court. She was relentless in her support and never received apologies from either politician even though the International Commission of Jurists concluded she was owed one because of how she was snubbed by the federal politicians opposed to her support of Nadon.
She also served as a non-permanent member of the Court of Final Appeal in Hong Kong.
After retiring, McLachlin began her writing career, writing a legal thriller, Full Disclosure and her memoir, Truth be Told: My Journey Through Life and the Law.
McLachlin has received 31 honorary degrees but remembered more for her legal philosophy that “that legal certainty [has only] one correct answer to a legal question…is a myth” and her work in developing Indigenous rights while she was in the high court of Canada.