How is the Prime Minister chosen?

Ordinarily, after an election, the leader of the political party with the most seats in the House of Commons is invited by the Governor General to form the government. After being appointed by the Governor General, the leader of this party becomes the Prime Minister. If the party in power holds at least half of the seats in the House of Commons, this is called a majority government. If the party in power holds less than half of the seats in the House of Commons, this is called a minority government. 

22nd, Prime Minister of Canada is the Conservative Party's Stephen Harper, who was appointed on February 6, 2006, by Governor General Michaëlle Jean