Wilfrid Laurier was an MP for 44 years and 11 months between January 22, 1874 and February 17, 1919, although his tenure was not continuous. He did serve continuously for 41 years and 2 months from November 28, 1877 to February 17, 1919, making him also the MP with the longest continuous service.
who is the longest serving parliamentarian in canada's history
Wilfrid Laurier