He is now returning to the USA, where his approval ratings are low.
Not that Trump himself admitted to any confrontation.
Trump reportedly described the Germans as "bad, very bad" in their trade practices while visiting Brussels this past week.
Down to the final day of his lengthy first worldwide trip, President Donald Trump will lift off for Washington having rattled some allies and reassured others, returning to a White House that sits under a cloud of scandal.
But as Air Force One lifted off, it became clear that wouldn't be the case.
Trip stops in Saudi Arabia and Israel and the Palestinian territories secured broadly favourable coverage with Trump seen by some commentators as having finally hit a presidential note.
German chancellor Angela Merkel admitted her discussion with Mr Trump had been "a very hard, not to say very unsatisfactory. meaning there is still no sign of whether the United States will remain in the Paris accord or not", she said.
Trump failed to reassure European leaders about his commitment to combating Russian aggression with his remarks at North Atlantic Treaty Organisation headquarters in Brussels and hours later, as he landed in Sicily for the G7, news broke that the Federal Bureau of Investigation was now looking into his son-in-law and senior adviser Jared Kushner's contacts with Russian officials.
Trump's visit to Saudi Arabia, the birthplace of Islam, gave Trump a chance to square U.S. government policy with the vitriol of his campaign on Islam and terrorism.More news: Hoyer: 'Abdication of American Leadership' Not To Back Climate Deal
The world has already warmed by just over half that amount - with about one-fifth of the past heat-trapping carbon dioxide emissions coming from the United States, usually from the burning of coal, oil and gas.
"We commit to adopting appropriate policies so that all firms and citizens can make the most of opportunities offered by the global economy", it says.
- Demanded support from Russian Federation and Iran for a peace process in Syria, and similarly called for an inclusive dialogue in Libya. The two leaders also spoke about boosting cooperation on counterterrorism efforts.
Those calls had mixed results. The U.S., he said, is "well positioned to compete" with the agreement in place and staying in means "a seat at the negotiating table to ensure a level playing field".
But his visit grew more complicated as he arrived in Europe, where he joined heads of state - many wary of his presidency - in groups and where the welcome was far more muted.
Broadcaster ABC News, meanwhile, chose to focus on the President's "awkward body language moments" - including pushing the Montenegrin prime minister out the way.
"He came here to learn", Cohn said at the G7 summit. In group photos, Trump towered above most leaders, and tilted his chin upward in pride as he walked among his counterparts.
The unexpected announcement came as a summit of G7 leaders in Sicily ended up in deadlock on the issue, with U.S. partners voicing frustration at the president's failure to commit to the deal aimed at stemming global warming. "Meeting the Paris Agreement's temperature limitation goals is in the environmental, economic and national security interests of the United States, whereas President Trump's "climate inaction plan" is a threat to every American's health and future prosperity".
"He feels much more knowledgeable on the topic today", Cohn said as the first day of G7 meetings wrapped.