Trump appeared at the White House for a "Liberation Day" ceremony where he announced the tariffs, including a 10 per cent baseline tax on imports from all countries and higher tariff rates on dozens of nations that run trade surpluses with the United States.
The measures threaten to upend much of the architecture of the global economy and trigger broader trade wars.
"This is one of the most important days in my opinion in American history. It's our declaration of economic independence," he said.
"For years, hardworking American citizens were forced to sit on the sidelines as other nations got rich and powerful, much of it at our expense. But now it's our turn to prosper."
Trump held up a chart showing the United States would charge a 34 per cent tax on imports from China, a 20 per cent tax on imports from the European Union, 25 per cent on South Korea, 24 per cent on Japan and 32 per cent on Taiwan.
The president used aggressive rhetoric to describe a global trade system that the United States helped to build after World War II, saying "our country has been looted, pillaged, raped, plundered" by other nations.
Trump declared a national economic emergency to launch the tariffs, expected to produce hundreds of billions in annual revenues.
He has promised that factory jobs will return to the United States as a result of the taxes, but his policies risk a sudden economic slowdown as consumers and businesses could face sharp price hikes on autos, clothes and other goods.
"Taxpayers have been ripped off for more than 50 years," Trump said in his remarks. "But it is not going to happen anymore."
The sweeping duties erect new barriers around the world's largest consumer economy, reversing decades of trade liberalisation that have shaped the global order.
Trading partners are expected to respond with countermeasures of their own that could lead to dramatically higher prices for everything from bicycles to wine.
The uncertainty has rattled financial markets and businesses that have relied on trading arrangements that have been in place since 1947.
The new tariffs were due to take effect immediately after Trump announces them.
Trump has already imposed 20 per cent duties on all imports from China and 25 per cent duties on steel and aluminium and extended them to nearly $US150 billion ($A238 billion) worth of downstream products.
He has postponed a 25 per cent tariff on most Canadian and Mexican goods to pressure them to crack down on drug trafficking and immigration, though that is due to expire on Wednesday.
Outside economists have warned that tariffs could slow the global economy, raise the risk of recession, and increase living costs for the average US family by thousands of dollars.
Across sectors, from cars to ocean freight shipping, luxury goods and beyond, business leaders waited to see what would hit them.
Tariff concerns have already slowed manufacturing activity across the globe, while also spurring sales of autos and other imported products as consumers rush to make purchases before prices rise.
Growing uncertainty over the duties is eroding investor, consumer and business confidence.
Global stocks retreated on Wednesday, while safe-haven gold held near record highs. US stocks have erased nearly $US5 ($A7.9) trillion of value since February.
With AP
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