Trudeau said he'd rather have no deal on NAFTA than one that isn't good for Canada.
Trudeau said he has deep concerns about Trump's demands, saying he is generally opposed to anything that creates instability in the supply chain.
The video went viral, with Twitter users coming out in force to condemn the Prime Minister.
Canadian Prime Minister Justin Trudeau will meet Amazon.com (AMZN.O) Chief Executive Jeff Bezos on Thursday during a tour of three major US cities this week to bolster support for the North American Free Trade Agreement, which is being renegotiated.
"Our economies have thrived over the past 25 years under NAFTA", he said.
Trudeau maintained that over the more than two decades that NAFTA has been in place, the American economy has also added 33 million net new jobs, which is nearly the entire population of Canada, some 36 million.
"Perhaps in the era of Trump, there are a lot of students who are looking north and feel a sense of identification with the sense of direction he's leading your country", said David Axelrod, a former top adviser to Barack Obama, who is moderating the event.
Much of Trudeau's speech had a rueful tone over the comparative claims of the Canadian and American nations on their neighbor's psyche.
"I'll be honest, I think he's going to get more attention if he paints a picture of what trade deals amongst these countries look like with America absent".
Trudeau left the stage to a standing ovation from the auditorium nearly filled to its capacity of about 1,000, wading through the crowd of students and shaking the occasional hand as The Tragically Hip's "Courage" played over the loudspeakers.
Canada is the state's top trading partner, said Todd Maisch, president and CEO of the Illinois Chamber of Commerce, which promotes local jobs and economic opportunity.
Trudeau began a four-day visit to the U.S. Wednesday, first visiting the University of Chicago's Institute of Politics, where he spoke about trade. Trudeau smiled and added, 'Well, yes, there's differences in how we said we'd do it'.
Trudeau also met Thursday with Amazon Chief Executive Jeff Bezos as Bezos considers the location for its second headquarters.