The president made the announcement Thursday afternoon. He was joined at the White House by steel workers.
The tariff places a 25 percent tax on imported steel and 10 percent on aluminum.
Canada and Mexico are exempt as Trump renegotiates the structure of the North American Free Trade Agreement with those countries.
Trump’s plan to institute the tariffs is meant to help secure American jobs.
“The workers who poured their souls into building this great nation were betrayed, but that betrayal is now over,” Trump said.
The president also spent part of the day meeting with representatives of the video game industry, looking into whether or not violent games are linked with violent behavior.