1857 to 2017.
George Brown 1857-1867
Archibald McKellar 1867-1868
Edward Blake 1868-1872
Sir Oliver Mowat 1872-1896
Arthur S. Hardy 1896-1899
Sir George William Ross 1899-1907
George P. Graham 1907
A.G. MacKay 1907-1911
Newton Wesley Rowell 1911-1917
William Proudfoot 1918-1919
Hartley Dewart 1919-1921
Wellington Hay 1922-1923
W.E.N. Sinclair 1923-1930
Mitchell Hepburn 1930-1942
Gordon Daniel Conant 1942-1943 (interim)
Harry Nixon 1943-1944
Mitchell Hepburn 1944-1945 (second time)
Farquhar Oliver 1945-1950
Walter Thomson 1950-1954
Farquhar Oliver 1954-1957 (second time)
John Wintermeyer 1957-1964
Andrew Thompson 1964-1967
Robert Nixon 1967-1976
Stuart Smith 1976-1982
David Peterson 1982-1990
Robert Nixon 1990-1991 (interim)
Murray Elston 1991 (interim)
Jim Bradley 1991-1992 (interim)
Lyn McLeod 1992-1996
Dalton McGuinty 1996-2013
Kathleen Wynne 2013-present