As the archdiocese is the metropolitan see of the ecclesiastical province that encompasses Southern Ontario and part of Northwestern Ontario in Canada, the archbishop also administers the bishops who head the suffragan dioceses of Hamilton, London, Saint Catharines, and Thunder Bay.

[3][4] On March 18, 1870,[A] the diocese was elevated to the status of archdiocese by Pope Pius IX while the First Vatican Council was in session.

John Joseph Lynch became the first archbishop of the newly-formed metropolitan see,[3][6][7] and received the pallium during his sojourn in Rome to attend the council.

[7] Ten men have been Archbishop of Toronto; another two were the bishop of its predecessor diocese.

Five archbishops – James McGuigan, Gerald Emmett Carter, Aloysius Ambrozic, Thomas Collins, and Leo – were elevated to the College of Cardinals.