Xi took centre stage at the Asia-Pacific Economic Co-operation summit that began on Friday in the South Korean city of Gyeongju, after Trump left the country a day earlier following deals with Xi meant to ease their escalating trade war.
The two-day 2025 APEC summit has been heavily overshadowed by the Trump-Xi meeting that was arranged on the sidelines.
Trump described his Thursday meeting with Xi as a roaring success, saying he would cut tariffs on China, while Beijing had agreed to allow the export of rare-earth elements and start buying American soybeans.
Their deals were a relief to a world economy rattled by trade tensions between the world's two largest economies.
Trump's decision to skip APEC fits with his well-known disdain for big, multi-nation forums, but his blunt dismissal of APEC risks worsening America's reputation at gathering that represents more than half of global goods trade.
"The more turbulent the times, the more we must work together," Xi said during APEC's opening session.
"The world is undergoing a period of rapid change, with the international situation becoming increasingly complex and volatile."
Xi called for maintaining supply chain stability, in a riposte to US efforts to decouple its supply chains from China.
He also expressed hopes to work with other countries to expand co-operation in green industries and clean energy.
On the sidelines of the summit, Xi had meetings with new Japanese Prime Minister Sanae Takaichi, Canadian Prime Minister Mark Carney and Thai Prime Minister Anutin Charnvirakul.
Xi will meet South Korean President Lee Jae-myung on Saturday for a meeting expected to discuss North Korea's nuclear program.
US Secretary of the Treasury Scott Bessent, who attended the summit on Trump's behalf, said a US move to rebalance its trade relationships would ensure that "each country operates on fair and reciprocal terms".
He said the US was "investing with its trading partners to build resilient production networks that reduce dependence on vulnerable sectors".
Established in 1989, APEC champions free and open trade and investment, but its region now faces challenges such as strategic competitions between the US and China, supply chain vulnerabilities, ageing populations and the impact of AI on jobs.
The US strategy has been shifted to economic competition with China rather than co-operation, with Trump's tariff hikes and "America first" agenda shaking markets and threatening decades of globalisation and multinationalism.
Opening the summit, Lee addressed leaders and other representatives from 21 Asia-Pacific Rim economies, calling for greater co-operation and solidarity in the face of "a rapidly changing international economic environment".
"It's obvious that we can't always stand on the same side, as our national interests are at stake. But we can join together for the ultimate goal of shared prosperity," Lee said.
Carney reiterated his government's plan to double its non-US exports in the next decade as he said "our world is undergoing one of the most profound shifts since the fall of the Berlin Wall".
Despite Trump's optimism after a 100-minute meeting with Xi, there continues to be the potential for major tensions between the countries, with both seeking dominant places in manufacturing and developing emerging technologies such as artificial intelligence.
South Korean officials said they have been communicating with other countries to prod members to adopt a joint statement so as not to repeat the failure to issue one in 2018 in Papua New Guinea due to US-China discord over trade.
