He was nominated by Prime Minister Stephen Harper to replace outgoing justice Marshall Rothstein and served in the role starting on August 31, 2015.

[1] Brown was nominated by Prime Minister Stephen Harper to replace retiring justice Marshall Rothstein on the Supreme Court of Canada.

The Toronto Star published an article from John Whyte, a professor emeritus at the Queen’s University Faculty of Law, criticizing the appointment.

Whyte called Brown unfit for the Court because of his political writings and activism, and also attacked Harper for even naming a justice so close to an election campaign.

[7] Brown would nonetheless be sworn in on August 31, 2015, and without a Parliamentary hearing as Harper had discontinued the voluntary practice with the appointment of Suzanne Côté a year prior.

The decision attacked a "culture of complacency" that had developed towards the speedy trial rights of the accused and radically altered the application of section 11(b) of the Charter, leading to numerous cases being thrown out on account of unreasonable delay.

In R v Le he co-wrote a majority opinion throwing out the conviction of a young Asian-Canadian man, holding that he had been detained during an interaction with the police and should've consequently been advised of his right to counsel.

[16] In June 2018, Brown wrote a high profile dissent with Justice Côté on the topic of religious freedom in the case of Law Society of British Columbia v. Trinity Western University.

[20] Following the decision, Sean Speer wrote in the National Post that Brown "has distinguished himself as a powerful critic of judicial overreach in general and progressive jurisprudence in particular.

He went on to write that his dissents "lay out an alternative viewpoint about the role of courts, the division of powers between Ottawa and the provinces and the relationship between the individual and the state.