The confrontation over US tariffs on steel and aluminum threatened to rupture the G7, which during its 43-year history has traditionally sought to find consensus on the economy and other issues.
Trump, who aides said has little interest in multilateralism, resumed his tirade against Canada and "unfair trade deals" with G7 countries early Friday morning. The White House said he would leave talks four hours earlier than originally planned.
By departing early, the US leader will miss talks about climate change and clean energy, and be out of the country by the time Canadian Prime Minister Justin Trudeau and other leaders begin closing news conferences likely to be laden with criticism of US trade policy.
"Looking forward to straightening out unfair Trade Deals with the G-7 countries. If it doesn't happen, we come out even better!" Trump tweeted early Friday morning before he was to leave Washington for Quebec.
Officials conceded the mood will likely be exceptionally tense.
"There will be some serious disagreements on a lot of things," a Canadian official told reporters late Thursday.
Although Trump said the tariffs are necessary to protect US industry, Canada and the European Union have denounced them as illegal and are preparing retaliatory measures.
French President Emmanuel Macron warned Trump in a rare rebuke on Thursday that the other six members of the G7 might form their own group, adding that "no leader was forever."
British Prime Minister Theresa May took a more measured tone, telling reporters she wanted the European Union to use restraint in retaliation against US tariffs and that the response must be proportionate and legal.
Trump showed no sign of backing down on Friday after earlier accusing both France and Canada of imposing massive tariffs on US goods, and then accusing Canadian Prime Minister Justin Trudeau of "being so indignant."
The Canadian official responded that "the prime minister and the president have very frank, direct, candid, honest conversations."
Trudeau and Trump are due to meet on Friday "and they will have lots to talk about," the official added.
The White House subsequently announced the president would leave on Saturday, before the summit formally ends, to fly to Singapore to meet with North Korean leader Kim Jong Un.
While the G7 chiefs have largely praised Trump for his efforts to stabilize the Korean peninsula, they are unhappy he pulled out of an agreement designed to limit Iran's nuclear ambitions.
The disputes threaten to derail a meeting that Trudeau had planned, focusing on inclusive growth, gender equality and protecting oceans.
The Canadian official said Trudeau remained optimistic that the summit could help find common solutions to issues such as growth and environmental protection.
In Germany, top officials called for Europe to remain unified in the face of rising trade tensions with the United States even as they maintained that America remained its closest partner outside the continent.