TORONTO - It is the dawn of a new era for the New Democratic Party as members ushered in a new leader Saturday night, Quebec MP Thomas Mulcair who has become known for having views that are far more to the centre than the party's founding philosophies.

Mulcair, a former Liberal cabinet minister who now represents the NDP riding of Outremont, received 57.2 per cent of members' support. Despite the party's old guard warning the membership of the danger Mulcair poses to the party's socially progressive values, Mulcair was the front-runner almost from the start of the campaign and held onto his lead until the final round of voting.

"Thank you to my fellow colleagues. We are celebrating today a victory for the members of the NDP who chose their own leader. Thank you and bravo to you," he yelled out into the crowd from on top of the stage with his wife by his side.

Mulcair will now serve as Leader of the Official Opposition in the House of Commons, leading the charge against Prime Minister Stephen Harper's Conservative government. 

The bilingual candidate took to the podium shortly after his victory had been declared, beaming before an exuberant crowd that had stayed at the Metro Toronto Convention Centre throughout the day, maintaining their energy despite numerous and repeated delays.

On stage, Mulcair recalled the times he was invited to political events by Jack Layton, the NDP's beloved leader who passed away last August after battling an aggressive form of cancer. His death sparked the leadership race and the seven-month campaign. 

He said at the time, he found it hard to get used to the idea of calling his colleagues "brothers and sisters."

But tonight, he addressed them as brothers and sisters and thanked them for their support.

Mulcair also took repeated jabs at the Conservative Party, calling for greater communication and action between governments and communities across the country, particularly youth.  He noted that youth, despite being engaged in current affairs, had become disenfranchised with politics.

He vowed to lead a party that would support communication "without excluding or demonizing those who disagree with us."

He ended his speech the way he started it -- in French, calling for a Canada "that is fairer and better."

His main rival in the race, long-time NDP strategist Brian Topp joined Mulcair briefly on stage, raising their clasped hands into the air in a show of support and unity.

Topp was one of Layton's top advisors and closest confidantes. He lost the race by 8,542 votes. Throughout the day, he was unable to secure enough votes from the camps of rivals who were forced out of the race to push him past the front-runner.

Only one of those candidates – Martin Singh -- openly backed Mulcair.

The other four candidates -- Churchill MP Niki Ashton, Ottawa MP Paul Dewar, Parkdale MP Peggy Nash and Skeena-Bulkley Valley MP Nathan Cullen – chose to remain neutral and told their supporters to vote as they saw fit.

However, each of those candidates took to Twitter to congratulate Mulcair on his new role.

"Congratulations to Thomas Mulcair. It was an honour and privilege to run in this race with you and I look forward to working with you," Cullen tweeted.

Cullen had reportedly dropped off a box of wild salmon to Mulcair's office to say thank you for the campaign.

Topp's active campaign

Despite Mulcair's strong numbers throughout the campaign and the convention, political strategists were keeping a close eye on Topp until the final round of voting.

Topp had an active campaign on the ground, even as the convention was going on. An automated phone bank had been set up in B.C. on his behalf and his team was actively reaching out to people who had still not voted for the party's new leader.

Alice Funke, publisher of PunditsGuide.ca said Topp needed to make the argument to voters that the party needed to stay the course that had brought it the success that it has enjoyed in the last year.

He would have had to tell people "we've fought too hard to get here and this is what Jack would have wanted," Funke said after the second round of voting. "(He would have had) to give people a stark choice."

Topp spoke to CP24.com just before the results of the second ballot. He said he knew he would be facing some tough rivals in this race.

"In the beginning, all the talk was about how unstoppable the campaign would be but I knew how good the candidates would be," he said. "We'll just have to see."

However, in what was perhaps a glimpse into his future, he said, "In the first ballot, people vote for who they love. In the second ballot, they vote for who they think should be leader."

Criticism of Mulcair

Funke had predicted the voting would go the full four rounds until a new leader was chosen.

"People vote for two reasons," she said. "They vote for what they want but more than that, they vote for what they don't want."

Mulcair had the largest crowd of supporters on the convention floor. He has now been endorsed by a number of high profile Canadians, including Torontonians City Councillor Maria Augimeri and Parkdale MPP Cheri DiNovo.

Nonetheless, his popularity had drawn a lot of criticism from the party's old guard, including Ed Broadbent who served as the party's leader for 14 years, from 1975 until 1989. Broadbent was active in Topp's campaign.

Mulcair's support for Israel and choice words for unions has left many in the NDP scratching their heads.

Sid Ryan, president of the Ontario Federation of Labour, called Mulcair quite simply, "a Liberal."

Ryan told CP24.com the leader of the NDP will need to keep the support of the party's base.

"We're a left of centre party. Anyone who pretends otherwise is a fool," he said.

Ryan was at the convention supporting Nash, but after the second ballot results were revealed, he was spotted walking around with a Brian Topp sticker on his orange scarf.

"I like him. Brian Topp has it all," he said.

But Layton's wife and colleague MP Olivia Chow told CP24 she wasn't too concerned when it came to the new leadership.

"It's not about being right or left of centre. We're going forward," she said. "Let's not get distracted. Their method might be different but the path is the same."

Low voter turnout

After the results of the first ballot was known, a lot of people took to Twitter to comment on the party's disappointing voter turnout, despite it being the largest leadership convention in the party's history.

About 65,000 votes were counted, including advanced polls (56,000 votes) and votes cast by more than 4,600 delegates attending the Toronto convention.

According to the NDP, there are 131,152 party members and eligible voters. That means that only about 51 per cent of delegates cast a ballot.

@SandieBenitah is on Twitter. For Instant breaking news, follow @CP24 on Twitter.