<P> Of the prime ministers who served less than one full term, two of them, Joe Clark and Paul Martin, had their time in office cut short by the collapse of a minority parliament and the subsequent election of the opposition party . In all other cases of short tenure, a new prime minister was put in place for the last few months of their predecessor's mandate--usually to try to gain support from the electorate before an election--but were subsequently defeated by the opposition party . The preceding Prime Minister always stays in office during an election campaign, and that time is included in the total . The first day of a Prime Minister's term is counted in the total, but the last day is not . This list is accurate as of January 8, 2018 . </P> <P> Liberal Party of Canada (10) Conservative Party of Canada (1) Historical conservative parties / Progressive Conservative Party of Canada (12) </P> <Table> <Tr> <Th> </Th> <Th> Prime Minister </Th> <Th> Incumbency </Th> <Th> Years in power </Th> <Th> Number of Mandates </Th> <Th> Remarks </Th> </Tr> <Tr> <Td> </Td> <Td> King! William Lyon Mackenzie King </Td> <Td> 7001210000000000000 ♠ 21 years, 7002154000000000000 ♠ 154 days </Td> <Td> 1921--1926, 1926--1930, 1935--1948 </Td> <Td> 3 majority & 3 minority </Td> <Td> William Lyon Mackenzie King served for three full terms in majority governments; two full terms in minority governments supported by opposition parties; and one short term under a minority government cut short by the King - Byng Affair after which he was replaced by Arthur Meighen . </Td> </Tr> <Tr> <Td> </Td> <Td> Macdonald! Sir John A. Macdonald </Td> <Td> 7001180000000000000 ♠ 18 years, 7002359000000000000 ♠ 359 days </Td> <Td> 1867--1873, 1878--1891 </Td> <Td> 6 majority </Td> <Td> Sir John A. Macdonald served for four full terms in majority governments; his second term in a majority government was cut short by the Pacific Scandal, with Alexander Mackenzie taking over; and one term in a majority government cut short by his death, after which four others served out the end of his final term . </Td> </Tr> <Tr> <Td> </Td> <Td> P.E. Trudeau! Pierre Trudeau </Td> <Td> 7001150000000000000 ♠ 15 years, 7002164000000000000 ♠ 164 days </Td> <Td> 1968--1979, 1980--1984 </Td> <Td> 3 majority & 1 minority </Td> <Td> Pierre Trudeau served for three full terms in majority governments and one short term in a minority government . The final months of his last term were served out by John Turner . </Td> </Tr> <Tr> <Td> </Td> <Td> Laurier! Sir Wilfrid Laurier </Td> <Td> 7003556300000000000 ♠ 15 years, 86 days </Td> <Td> 1896--1911 </Td> <Td> 4 majority </Td> <Td> Sir Wilfrid Laurier served for four full terms in majority governments . He served the longest uninterrupted term of any prime minister . </Td> </Tr> <Tr> <Td> </Td> <Td> Chrétien! Jean Chrétien </Td> <Td> 7003369000000000000 ♠ 10 years, 38 days </Td> <Td> 1993--2003 </Td> <Td> 3 majority </Td> <Td> Jean Chrétien served for three full terms in majority governments . The final six months of his last term were served out by Paul Martin . </Td> </Tr> <Tr> <Td> 6 </Td> <Td> Harper! Stephen Harper </Td> <Td> 7003355800000000000 ♠ 9 years, 271 days </Td> <Td> 2006--2015 </Td> <Td> 1 majority & 2 minority </Td> <Td> Stephen Harper served for two short terms in minority governments and one full term in majority government . </Td> </Tr> <Tr> <Td> 7 </Td> <Td> Mulroney! Brian Mulroney </Td> <Td> 7003320300000000000 ♠ 8 years, 281 days </Td> <Td> 1984--1993 </Td> <Td> 2 majority </Td> <Td> Brian Mulroney served for two full terms in majority governments . The final months of his last term were served out by Kim Campbell . </Td> </Tr> <Tr> <Td> 8 </Td> <Td> Borden! Sir Robert Borden </Td> <Td> 7003319600000000000 ♠ 8 years, 274 days </Td> <Td> 1911--1920 </Td> <Td> 2 majority </Td> <Td> Sir Robert Borden served for two full terms in majority governments . The final year and a half of his last term were served out by Arthur Meighen . </Td> </Tr> <Tr> <Td> 9 </Td> <Td> St. Laurent! Louis St. Laurent </Td> <Td> 7003314000000000000 ♠ 8 years, 218 days </Td> <Td> 1948--1957 </Td> <Td> 2 majority </Td> <Td> Louis St. Laurent served out the end of William Lyon Mackenzie King's last term after the latter's retirement . He then served for two full terms in majority governments . </Td> </Tr> <Tr> <Td> 10 </Td> <Td> Diefenbaker! John Diefenbaker </Td> <Td> 7003213100000000000 ♠ 5 years, 305 days </Td> <Td> 1957--1963 </Td> <Td> 1 majority & 2 minority </Td> <Td> John Diefenbaker served for one full term in a majority government and two short terms in minority governments . </Td> </Tr> <Tr> <Td> 11 </Td> <Td> Bennett! R.B. Bennett </Td> <Td> 7003190300000000000 ♠ 5 years, 77 days </Td> <Td> 1930--1935 </Td> <Td> 1 majority </Td> <Td> R.B. Bennett served for one full term in a majority government . </Td> </Tr> <Tr> <Td> 12 </Td> <Td> Pearson! Lester B. Pearson </Td> <Td> 7003182500000000000 ♠ 4 years, 364 days </Td> <Td> 1963--1968 </Td> <Td> 2 minority </Td> <Td> Lester B. Pearson served for two short terms in minority governments . The final months of his last term were served out by Pierre Trudeau . </Td> </Tr> <Tr> <Td> 13 </Td> <Td> Mackenzie! Alexander Mackenzie </Td> <Td> 7003179700000000000 ♠ 4 years, 336 days </Td> <Td> 1873--1878 </Td> <Td> 1 majority </Td> <Td> Alexander Mackenzie took over from Sir John A. Macdonald's first block of terms following the Pacific Scandal . He then served for one full term in a majority government . </Td> </Tr> <Tr> <Td> 14 </Td> <Td> J. Trudeau! Justin Trudeau (incumbent) </Td> <Td> 7002796000000000000 ♠ 2 years, 65 days </Td> <Td> 2015--present </Td> <Td> 1 majority </Td> <Td> Justin Trudeau is currently serving his first term of office leading a majority government . </Td> </Tr> <Tr> <Td> 15 </Td> <Td> Martin! Paul Martin </Td> <Td> 7002787000000000000 ♠ 2 years, 56 days </Td> <Td> 2003--2006 </Td> <Td> 1 minority </Td> <Td> Paul Martin served out the end of Jean Chrétien's last term after the latter's retirement . He then served for one short term in a minority government . </Td> </Tr> <Tr> <Td> 16 </Td> <Td> Thompson! Sir John Thompson </Td> <Td> 7002737000000000000 ♠ 2 years, 7 days </Td> <Td> 1892--1894 </Td> <Td> none </Td> <Td> Sir John Thompson was the second of four prime ministers to serve out the end of Sir John A. Macdonald's last term after Macdonald's death . He was the second, and currently last prime minister of Canada to die in office . He never won an election of his own . </Td> </Tr> <Tr> <Td> 17 </Td> <Td> Meighen! Arthur Meighen </Td> <Td> 7000100000000000000 ♠ 1 year, 7002260000000000000 ♠ 260 days </Td> <Td> 1920--1921, 1926 </Td> <Td> none </Td> <Td> Arthur Meighen served out the end of Sir Robert Borden's last term after the latter's retirement . He also briefly took over from William Lyon Mackenzie King's second term following the King - Byng Affair . His party had won more seats than King in the 1925 election, but did not win a majority . King was able to keep governing with the support of the Progressives until defeated in a confidence vote . The Governor - General then appointed Meighen as prime minister, but his government was soon defeated in a confidence vote as well and lost the resultant 1926 federal election . </Td> </Tr> <Tr> <Td> 18 </Td> <Td> Abbott! Sir John Abbott </Td> <Td> 7002527000000000000 ♠ 1 year, 161 days </Td> <Td> 1891--1892 </Td> <Td> none </Td> <Td> Sir John Abbott was the first of four prime ministers to serve out the end of Sir John A. Macdonald's last term after Macdonald's death . Due to health reasons he did not finish the term . He never won an election of his own . </Td> </Tr> <Tr> <Td> 19 </Td> <Td> Bowell! Sir Mackenzie Bowell </Td> <Td> 7002493000000000000 ♠ 1 year, 128 days </Td> <Td> 1894--1896 </Td> <Td> none </Td> <Td> Sir Mackenzie Bowell was the third of four prime ministers to serve out the end of Sir John A. Macdonald's last term after Macdonald's death . He lost the confidence of his cabinet and resigned before the end of the term . He never won an election of his own . </Td> </Tr> <Tr> <Td> 20 </Td> <Td> Clark! Joe Clark </Td> <Td> 7002273000000000000 ♠ 273 days </Td> <Td> 1979--1980 </Td> <Td> 1 minority </Td> <Td> Joe Clark served one short term in a minority government . </Td> </Tr> <Tr> <Td> 21 </Td> <Td> Campbell! Kim Campbell </Td> <Td> 7002132000000000000 ♠ 132 days </Td> <Td> </Td> <Td> none </Td> <Td> Kim Campbell served out the end of Brian Mulroney's last term after the latter's retirement . She never won an election of her own . </Td> </Tr> <Tr> <Td> 22 </Td> <Td> Turner! John Turner </Td> <Td> 7001790000000000000 ♠ 79 days </Td> <Td> 1984 </Td> <Td> none </Td> <Td> John Turner served out the end of Pierre Trudeau's last term after the latter's retirement . He never won an election of his own . He may have been one of two prime ministers who never served as a Member of Parliament or Senator during any point of his tenure as prime minister . Some sources, however, report that he was sworn in as member for Vancouver Quadra a short time before he resigned as prime minister . </Td> </Tr> <Tr> <Td> 23 </Td> <Td> Tupper! Sir Charles Tupper </Td> <Td> 7001680000000000000 ♠ 68 days </Td> <Td> 1896 </Td> <Td> none </Td> <Td> Sir Charles Tupper was the fourth of four prime ministers to serve out the end of Sir John A. Macdonald's last term after Macdonald's death . He never won an election of his own . He was only in power during an election campaign, making him one of two prime ministers, and perhaps the only one, who never served as a Member of Parliament or Senator during any point of his tenure as prime minister . </Td> </Tr> </Table> <Tr> <Th> </Th> <Th> Prime Minister </Th> <Th> Incumbency </Th> <Th> Years in power </Th> <Th> Number of Mandates </Th> <Th> Remarks </Th> </Tr>

Who was canada's longest serving prime minister