The U.S. administration is probing whether foreign-made steel and aluminum imports pose a risk. The investigation is almost complete, officials say.
Although Trudeau said last month he had pressed Trump to exclude Canada, his remarks on Friday were the first to reveal the president's response.
"I've heard from President Trump as well that he does not think that Canada should be subject to national security concerns around the trade in steel and aluminum," Trudeau told reporters at the U.S. National Governors Association meeting in Providence, Rhode Island.
"I am optimistic that this important trade, which leads to millions of good jobs on both sides of the border, will continue," he added.
Trudeau said last month it was "just silly" to imagine Canadian exports were a threat to the United States, given how closely the two nations' militaries and security forces cooperated.