<page_title> List of Prime Ministers of Canada by longevity </page_title> <section_title> Oldest living Prime Ministers of Canada </section_title> <table> <cell> Louis St. Laurent <col_header> Prime Minister </col_header> </cell> <cell> 78 years, 186 days <col_header> Age at start date </col_header> </cell> </table>
Louis St. Laurent was the oldest to become Prime Ministers of Canada at the age of 78 years and 186 days.