The convention was to be held at Exhibition Place's Allstream Centre, but it was moved to the larger venue due to a greater than expected number of delegates registering for the event.

[3] Others, including party president Brian Topp and Deputy Leader Tom Mulcair—both prospective candidates—called for a longer race.

[7] Also in that election, affiliated organizations (such as trade unions) were allotted a minimum of 25 percent of the vote, with the remainder held by individual party members.

[8] Party president and leadership candidate Brian Topp supported retaining the carve-out as did former MP Dawn Black, while MPs Thomas Mulcair, Peter Stoffer, and Pat Martin opposed it.

[5] On September 14, 2011, interim party leader Nycole Turmel announced rules for candidates from the federal caucus that would have members of the caucus executive, e.g., deputy leaders, to stay in their posts, but would require critics and committee chairs and vice chairs to step down if they chose to join the race.

[11] All those who were party members by February 18, 2012, were eligible to vote and could do so in one of three ways: The candidates participated in six debates, in Ottawa, Halifax, Quebec City, Winnipeg, Montreal and Vancouver.

Before becoming involved in politics, Cullen worked in community and economic development throughout Latin America, North America and Africa and also started his own business, Maravilla Consultants, providing strategic planning and conflict resolution services to business, government, and non-profit agencies throughout B.C.

[32] Cullen had served as a critic in the NDP shadow cabinet, first for environment, national parks and youth, then natural resources and energy.

In the 2011 Parliament, Cullen served as Chair of the House of Commons Standing Committee on Privacy, Access to Information and Ethics.

[34] In the 2011 federal election, Cullen received over 55% of the popular vote in his constituency, the highest plurality in the region since 1962.

[130] On December 11, 2005, he was elected president of the Maritime Sikh Society,[132] and is the first person of non-Indian ethnicity to become head of a gurdwara in Canada.

[77] Brian Topp was President of the NDP from its 2011 convention; he did not participate in establishing the rules of the campaign and resigned to enter the leadership race.

He was previously deputy chief of staff to Saskatchewan Premier Roy Romanow (1993–2000) and senior adviser to Jack Layton during the 2011 election campaign.

[175] In 1998, he led the NDP to official opposition, the first time since the party's predecessor Co-operative Commonwealth Federation (CCF) accomplished that feat in the 1940s under Donald MacDonald.

[174] Chisholm withdrew his candidacy on December 21, 2011, citing his lack of fluency in French,[179] and on February 29, 2012, endorsed Thomas Mulcair for leadership.

[183] Saganash announced on February 9, 2012, that he was withdrawing from the race, citing illness in his family and a lack of confidence in his campaign.

[206] A survey conducted by Leger Marketing between September 12 and 15, 2011, found that 17% of NDP supporters favoured Mulcair as leader.

[208] A Harris-Decima poll conducted between September 1 and 4, 2011, showed support for Chow at 19%, Mulcair at 14%, Gary Doer at 6%, Paul Dewar at 3%, and Libby Davies, Topp, Peter Julian and Robert Chisholm all at 2%.

The remaining 53% of supporters were split between Thomas Mulcair (45%), Peggy Nash (16%) with Paul Dewar and Brian Topp at 8%.

[210] A survey conducted by Abacus Data asked respondents whether they were aware of the candidates running for the leadership of the NDP.

[211] A Forum Research poll for the National Post on January 18, 2012, surveyed 1,200 Canadians on their opinions for NDP leader.

Of those surveyed, 14% supported Thomas Mulcair, followed by 6% for Peggy Nash, 5% each for Brian Topp and Paul Dewar, 3% for Romeo Saganash, and 2% each for Niki Ashton, Nathan Cullen, and Martin Singh.

With responses from 6,373 households in "every region of Canada", the first choice responses weighted by NDP membership per province for decided voters were: Thomas Mulcair 25.5%, Peggy Nash 16.8%, Paul Dewar 15.1%, Nathan Cullen 12.8%, Brian Topp 12.7%, Niki Ashton 9.5%, Martin Singh 4.1%, Romeo Saganash 3.6%.

Pundits had comparisons with New Labour in Britain under Tony Blair and Gordon Brown, with Mulcair's stance on the party.

[219][220][221] Brian Topp was considered to have one of the most polished presentations, while Nathan Cullen distinguished himself by speaking without notes or a teleprompter.

[223][224] Voting for the first round ended up at roughly half the 128,351 eligible voters, lower than expected but still much higher than the usual participation rates at conventions.