"This was a very big day for free and fair trade", Trump said during a hastily scheduled joint appearance in the White House Rose Garden with Juncker, hailing a "new phase" of trade relations with the EU.
The tweet came on the same day that Trump issued this one, amid news that his administration was starting a $12 billion plan to help US farmers amid trade disputes.
The Trump administration has imposed tariffs on $34 billion in Chinese goods in a dispute over Beijing's high-tech industrial policies and has threatened to eventually target $500 billion.
But Trump agreed to "resolve" existing USA tariffs on European steel and aluminum as well as Europe's retaliatory tariffs against American motorcycles, bourbon and other products.
Unfortunately, America's hard-working agricultural producers have been treated unfairly by China's illegal trading practices and have taken a disproportionate hit when it comes to illegal retaliatory tariffs, he said.
Trump has so far suffered little political blowback for his tariffs and trade threats, saying that he is simply following through on promises he made during the campaign to crack down on trading partners, even close allies, and put America first.
Mark Martinson, who raises crops and cattle in north-central North Dakota and is president of the U.S. Durum Growers Association, said the $12 billion figure "sounds huge" but there are many farmers in need.
High tariffs disrupt normal marketing patterns, affecting prices and raising costs by forcing commodities to find new markets.
The White House argues that the short-term pain from retaliatory tariffs is negligible compared to the benefits the country stands to reap from fair trade deals and lowered trade barriers.
Schweitzer said European companies also faced other non-tariff barriers to doing business in the United States, for instance in winning government contracts, or due to the different regulations in various USA states. He's felt the impact of the trade wars directly as milk prices plummeted again this year following a long downward slide.
Juncker came to Washington for a last-ditch bid to avoid USA tariffs on cars.
Mr Trump, speaking at an event in Kansas City on Tuesday, reaffirmed his support for tariffs and pledged that "farmers will be the biggest beneficiary".
The US President often reaches out to make close contact with world leaders and was filmed holding hands with Prime Minister Theresa May during his visit to the United Kingdom last week. The Department of Agriculture will determine the payment to each farmer based on the size of a crop multiplied by a specific subsidy rate.
Minutes later, at a conference at the Center for Strategic and International Studies, Juncker said that the agreement emphasised the "special" nature of the alliance between the USA and the European Union going on to stress that trade between the two parties comprises half of all global commerce.
The deal eases tensions stoked by Trump's threat to impose new tariffs on vehicle imports.
"Auto tariffs are looming unless the European Union buys more USA stuff and does other things Trump demands", he said.
The US will not impose tariffs on European Union cars and might take back ones on steel and aluminium, but the European Union will buy more US soybeans and gas, according to a deal in Washington on Wednesday (25 July).
China cancelled almost $140 million in soybean contracts at the end of June, according to United States lawmakers.
The breakthrough came as the bitter trade dispute between the United States and China appeared to claim a major casualty, with China not approving U.S. chipmaker Qualcomms takeover of NXP Semiconductors, likely shutting the door on the $44bn deal.