The calm and soft-spoken Lester Pearson, recipient of the Nobel Peace Prize, was ironically the prime minster with the longest war experience.

Pearson enlisted with the Canadian Army Medical Corps in April 1915, as soon as he turned 18, and served as a medical orderly in England, Egypt and Greece, including stints as a stretcher-bearer, rising from private to lieutenant. In 1917, he transferred to the Royal Flying Corps, where he was nicknamed Mike. His flying instructor thought ‘Lester’ was not threatening enough for a fighter pilot.

Pearson’s fighter pilot ambitions were cut short by injuries from accidents, including a plane crash and being hit by a bus in 1918 during a blackout, after which he was invalided home.

After the war, he had a brief academic career before beginning three decades of diplomatic service, lasting through the Second World War, and ending as ambassador to the United States after the war. His political career began with the 1948 election, and his subsequent appointment as external affairs minister.

In the 1940s and ’50s, he worked for the establishment of the United Nations and NATO, heading the Canadian delegations to each, and served as NATO Council chair in 1951-52 and as president of the UN General Assembly in 1952-53.

After the United Kingdom, France and Israel invaded Egyptian territory in 1956 following nationalization of the Suez Canal by Egypt, Pearson sponsored a resolution to create an armed UN emergency force to police the area, earning him the Nobel Peace Prize.

From 1963 to 1968, he served as Canada’s 14th prime minister, heading two fractious minority governments that nevertheless left a notable legislative legacy: universal health care, the Canada Pension Plan, the Maple Leaf flag and student loans.

In 1965, he introduced a motion to adopt “O Canada” as the official anthem, but he did not live to see it. Though a joint Senate and Commons committee approved of it in 1967, more than a dozen bills were introduced before one finally passed. “O Canada” became the official anthem in 1980.

Pearson died on Dec. 27, 1972.