In brief remarks, Johnson seemed to actually take issue with Trump's tactics.
"We think that on the whole the UK has profited massively in the last 200 years from free trade," Johnson said.
Trump and Johnson are in France for the Group of Seven summit, an annual gathering of world leaders where they typically discuss pressing issues. So far, leaders appear far apart on Trump's approach to trade, but the American president has complained about the press coverage of his meetings so far, painting his interactions as very successful and cordial.
"Well, we are having very good meetings, the Leaders are getting along very well, and our Country, economically is doing great — the talk of the world!" he wrote on Twitter.
This was one of two Twitter posts in which Trump claimed that the strength of the US economy was the subject of multiple conversations here, although none of the other leaders have publicly made any such comments to corroborate his claim.
Sunday was set to be a pivotal day for each of the leaders, as they wade into thorny discussions about the faltering global economy.
After the breakfast between Trump and Johnson, leaders are also scheduled to hold a roundtable about the economy, which will give them a concrete opportunity to air their concerns.
Trump has at times boasted that the US economy is performing much better than other countries, and he has said there is a global recession that is harming most of the major nations except for the United States. Other leaders have said Trump's trade war is causing global supply chains to seize up, and there is evidence the US economy is slowing much more quickly than anticipated.
Just in the past week, Trump has swung wildly in his approach to the economy, saying he is contemplating tax cuts, then saying tax cuts aren't needed, and then on Saturday saying he planned to pursue tax cuts in 2021.
Trump's attempt to create a counter narrative at the summit came as other world leaders, in public statements, described the global dynamic as being in a state of crisis. French President Emmanuel Macron caught Trump off guard when during a lunch together he said they needed to discuss ways to address growing tensions over trade.
Johnson has also said he will push Trump to de-escalate trade tensions, and European Council President Donald Tusk questioned Trump's political motives for dramatically escalating his trade disputes with China in recent days.
The glowing reviews Trump has given the summit so far also conflict with assessments from some of his own aides, who have expressed fury that French officials had steered the subject matter of the summit into areas that Trump has little interest. But other administration officials have said privately that the meetings are going well and have struck a positive tone.
The G-7 countries include the United States, France, Britain, Germany, Italy, Japan, and Canada. The gatherings are typically capped off with a joint statement, known as a communique, that is meant to reflect the leaders' shared values and goals.
Last year's summit, hosted by Canada, was a spectacular failure, as Trump attempted to withdraw from the communique after the meeting ended because he felt personally slighted by comments from Canada's leader, Justin Trudeau.
This year, officials have openly floated the possibility that there won't even be a communique, trying to downplay expectations at a time when global relations are only worsening.
Trump has disrupted numerous international summits and has appeared at ease by putting other leaders on edge. His "America First" slogan drives a US-centric agenda that White House officials have said is one reason the president remains very popular with his supporters.
But Trump is under growing pressure domestically, particularly from farmers and other business leaders, to explain his approach to trade. Trump has imposed a series of harsh economic penalties against Chinese imports, and China has retaliated at almost every step. Relations worsened markedly last week, and Trump vowed more punitive measures were coming.
Other leaders at the G-7 have also complained about China's tactics but they have questioned Trump's decision to keep ratcheting up tariffs in a way that drives up costs for global consumers.
Early Sunday morning, Trump remarked on his initial meetings at the summit by saying "Progress being made!"
It wasn't immediately clear what issue he believed the White House was making progress on.
