Many of the several hundred in the crowded banquet hall told CBC's Amanda Margison they were supporting Trudeau's leadership bid, with some wearing Justin Trudeau T-shirts and a few carrying photos of him and a pen, hopeful for an autograph.
But others said Trudeau would have to convince them he's the right choice.
Kiros Fanous, a 21-year-old pharmacy grad still looking for a job, said he was hearing Trudeau speak for the first time.
"He hasn't said that many specifics in this campaign stop," Fanous said. "The only specifics I can think of is education and saying he isn't going to focus on the past, which Liberals have done before. So that sounds good to me. I have to maintain skepticism because I haven't seen anything."
Any Liberal leader would have to reverse the party's fortunes in the areas around Toronto if they hope to form the next government. The Liberals suffered a stunning collapse there in the last federal election, losing all but one of their seats in the 905 region to the Conservatives.
Leadership vote still six months away
Trudeau says he is trying to engage young people, the middle class and immigrants — messages he delivered in his earlier campaigns stops this week.
The Liberal leadership vote isn't for another six months. So far, only Trudeau and Deborah Coyne have declared an intention to lead the party.
Trudeau is capping his first week as a candidate for the federal Liberal leadership Friday with an endorsement from a one-time contender for the party's top job.
New Brunswick MP Dominic LeBlanc, a lifelong friend, is to endorse Trudeau at an event in his Beausejour riding.
LeBlanc's late father, former governor general Romeo LeBlanc, served in the cabinet of Trudeau's late father, former prime minister Pierre Trudeau.
LeBlanc briefly ran for Liberal leader in 2008, before stepping aside to allow a coronation for Michael Ignatieff.
Although he'd mused publicly about running again this time, he'd made no effort to put together a campaign team and few Liberals actually expected him to take the plunge.
An insider close to Trudeau said no pressure was put on LeBlanc to stand aside in favour of his childhood playmate.