Born in Mount Forest, Ontario, he received a Bachelor of Arts degree from the University of Toronto in 1909.

In 1918, he accepted the position of Secretary for the Canadian Council of Agriculture and Associate Editor of the Grain Growers' Guide in Winnipeg.

In 1932, he was appointed General Secretary and Chief Organizer of the National Liberal Federation and was the party's president from 1936 to 1941.

In 1938, he was summoned to the Canadian Senate on the advice of Mackenzie King representing the senatorial division of Ottawa, Ontario.

Following his term as NLF president, Lambert took on a position managing the federation's financial interests and also served as a director of the Liberal Realty Company and in these positions played a role in obtaining a building to house the party's headquarters.