OTTAWA—Canada’s Finance Minister Chrystia Freeland quit the Liberal government cabinet Monday, a surprise departure that casts further doubts about how long Prime Minister Justin Trudeau can hold on to his job given the government’s deep unpopularity.

Canadian Prime Minister Justin Trudeau is facing the biggest test of his political career following the resignation of Finance Minister Chrystia Freeland, long one of his most powerful and loyal ministers.

Prime Minister Justin Trudeau faced frustrated MPs at a hastily arranged caucus meeting late Monday following Chrystia Freeland's shocking decision to resign from cabinet just before she was poised to deliver the government's much-anticipated fall economic statement.