John George Diefenbaker was a successful lawyer in Saskatchewan when the political bug bit him. He was first elected in 1940, but did not win the leadership of the renamed Progressive Conservative Party until 1956.
He served as Prime Minister from 1957 to 1963. In 1961, he made a contribution to Medicare by setting up a Royal Commission on Health Care. However, by the time the commission reported in 1964, Diefenbaker was no longer Prime Minister. The task of making Medicare happen fell to Lester Pearson, the next PM.
Diefenbaker also created Canada's first Bill of Rights, but it was not entrenched in the constitution. In the rights arena, he was the PM who finally gave the unconditional right to vote to aboriginal people in federal elections.
Diefenbaker's government got into trouble over the Avro Arrow, a Canadian-designed fighter aircraft which was scrapped by the Conservatives in mid-development. As if that were not enough, the government insisted that the prototypes as well as the plans be destroyed.
The reasons given to the public were that the plane was too expensive to produce and not enough could be sold to justify the cost. Many were unhappy with this decision, and various conspiracy theories have been propounded about possible nefarious reasons for what was seen as an attack on Canadian design, ingenuity and industry.
A more popular, although also controversial decision made by Diefenbaker was that there would be no nuclear weapons in Canada.