He said the US expected to collect $100bn (£77bn) from the new tariffs and would buy “agricultural products from our great farmers, in larger amounts than China ever did, and ship it to poor & starving countries in the form of humanitarian assistance”.
Mr Trump has insisted that China would pay the tariffs, not American consumers, however prices have risen on a number of products as US businesses shoulder the costs.
A study by the Federal Reserve Bank of New York and Columbia and Princeton universities published in March found Mr Trump's combative trade policy was costing US consumers and firms $3bn a month in extra taxes.
In a flurry of early morning tweets on Friday – the first of which were deleted and then tweeted again half an hour later – the president said talks with China were continuing in a "very congenial manner" but added there was "absolutely no need to rush".
He urged Americans to "sit back and watch" as the escalating trade war with China made the US "much stronger", without elaborating on exactly what form the new strength would take.
"This is not the Obama Administration, or the Administration of Sleepy Joe, who let China get away with 'murder!'," he posted, using the nickname he has given the 2020 Democratic frontrunner, Joe Biden.
On Friday, a further $200bn worth of tariffs were imposed on Chinese imports, despite talks resuming on Thursday to find a way to defuse tensions between Washington and Beijing.
The higher import taxes won't hit goods that already left Chinese ports before Friday's deadline. Only when those shipments complete the three- to four-week voyage across the Pacific to the US would they face the new 25 per cent tariff - up from 10 per cent.
China said on Friday it would take "necessary countermeasures", having responded to earlier US tariff hikes by imposing penalties on $110bn of American imports.
However it is now running out of goods for retaliation due to the lopsided trade balance.
Additional reporting by AP