McLellan served as Minister of Justice from 1997 to 2002, with responsibility for implementing new anti-terror and security laws following the September 11, 2001, attacks in the United States, and the implementation of the Canadian gun registry.
Though she supported Paul Martin for the Liberal leadership, she was kept in Jean Chrétien's cabinet due to her ability and also because Chrétien wanted an Albertan in his cabinet for the sake of regional representation.