At 11 weeks, the ensuing campaign was one of the longest in Canadian history:[2] It was also the first time since the 1979 election that a prime minister attempted to remain in office into a fourth consecutive Parliament and the first time since the 1980 election that someone attempted to win a fourth term of any kind as prime minister.

The Liberal Party won 184 seats, forming a majority government with its leader Justin Trudeau becoming prime minister.

[4] The Conservative Party, led by incumbent Prime Minister Stephen Harper, won 99 seats, becoming the Official Opposition after nearly a decade on the government benches.

[6] Following the election, Harper conceded defeat to Trudeau and resigned as leader of the Conservative Party.

Tom Mulcair announced his intention to remain leader of the NDP, but was forced to step down in October 2017, after losing a party vote on his leadership in the spring of 2016.

The Bloc Québécois lost official party status by failing to attain the minimum seats needed (12).

In July 2011 Jack Layton, suffering from cancer, temporarily stepped down as leader of the NDP because of illness, indicating his intention to return for the reconvening of Parliament in September.

[14] Traditionally, party leaders participated in at least two nationally televised debates during the federal election – at least one each in English and French.

[27][30][32][33] Strength in Democracy, which had the same number of seats in the House of Commons at dissolution as the Greens and Bloc Québécois, were not invited to participate in any of the televised debates.

The second Canadian federal election to significantly incorporate social media, the 2015 campaign was notable for the rise of new avenues of scrutiny for potential candidates.

Evolution of voting intentions during the campaign leading up to the 2015 Canadian federal election to be held on October 19, 2015.

Similarly, candidates (through their official agents) receive a reimbursement of 60 per cent of their election expenses during the writ period.

Lawrence Martin, commentator for The Globe and Mail said, "Harper has completed a remarkable reconstruction of a Canadian political landscape that endured for more than a century.

"[99] Andrew Coyne, writing in Maclean's, said the election marked "an unprecedented realignment of Canadian politics" as "the Conservatives are now in a position to replace the Liberals as the natural governing party in Canada.

"[100] Despite the grim outlook and poor early poll numbers, when the 2015 election was held, the Liberals under Trudeau made an unprecedented comeback.

[101] Chantal Hébert, writing in the Toronto Star, claimed the comeback was "headed straight for the history books" and that Harper's name would "forever be joined with that of his Liberal nemesis in Canada's electoral annals".

[102] Spencer McKay, writing for the National Post, suggested that "maybe we've witnessed a revival of Canada's 'natural governing party'".