By Agence France-Presse
At the same time, she rejected US President Donald Trump's linkage of the levies to ongoing continental free trade talks.
"Today is a step forward. There is more hard work to do," Freeland told a news conference.
"In recent days, we have worked energetically with our American counterparts to secure an exemption for Canada from these tariffs," she said.
"This work continues and it will continue until the prospect of these duties is fully and permanently lifted."
Senior Canadian officials including the prime minister made a flurry of calls Wednesday and Thursday to American lawmakers and White House officials, hoping to head off the levies.
Canada is the largest foreign supplier of steel and aluminum to the United States.
In her comments, Freeland pilloried the US national security justification for the measure, saying: "That Canada could pose any kind of security threat to the United States is inconceivable."
She also called the steel and aluminum tariffs and the North American Free Trade Agreement negotiations "separate issues," but added that a NAFTA deal was "within reach."
Canadian, Mexican and US trade officials are scheduled to meet in Washington at the end of the month for the next round of NAFTA negotiations.