The two men joked about greying hair and traded compliments about their spouses and kids, even as Trudeau said he would not reconsider a decision to pull Canadian jets out of Iraq and Syria.
"I made a clear commitment to Canadians to withdraw the six fighter jets," Trudeau said.
Obama's administration has tried to bind allies into a coalition fighting Islamic State and lessen the burden on the US military.
"Canada will and must remain a strong member of the coalition," Trudeau said on the sidelines of a trade summit in Manila.
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Trudeau said he will ramp up Canada's commitment to training forces fighting the violent Islamist group.
Canada last year deployed 69 military trainers to northern Iraq to train Kurdish militia, as well as six CF-18 fighter jets that have conducted 1,121 sorties in Iraq and Syria as of November 15.
"There is much that Canada can do and Canada will continue to work with our coalition partners to ensure that we're doing what we can, including militarily, to degrade and defeat ISIL over the long haul," he said using an acronym for Islamic State.
"I'm confident that he's going to be able to provide a great boost of energy and transform the Canadian political landscape," Obama said, inviting Trudeau to visit Washington.
"The first call I made to him, I said, 'Justin, congratulations. You and your family look great. I know Canadians are incredibly inspired by your message of hope and change,'" Obama said, echoing the messages of his own 2008 election campaign.
"I just want to point out that I had no grey hair when I was in your shoes seven years ago. So if you don't want to grey like me you have to start dying it soon. Because it's too late."