Tusk said it was "time to turn our successes into joint action," pointing to the large Vietnamese community in Poland as an important link between the two countries.
Hung told reporters that Poland was Vietnam’s most important partner in Central Europe.
Defence will be a new pillar of the partnership, Vietnam's PM added, with cooperation on security, including the fight against cybercrime.
Tusk said Poland welcomed Vietnam’s interest in its defence industry and that talks were under way.
On trade, Hung announced that the two sides would set up a joint committee with the aim of reaching USD 6 billion in mutual investment by 2030.
Tusk said the EU-Vietnam free trade agreement had opened new opportunities, but that Polish companies still faced barriers to entering the Vietnamese market.
Poland would seek better terms for its agricultural and food exports, and for Polish investors in sectors including pharmaceuticals, IT and green technology.
Improving the balance of trade remained a priority, he added.
The two leaders also discussed Russia's war in Ukraine.
Tusk acknowledged that Vietnam viewed the conflict from a different perspective, but said both sides agreed that their own histories of war meant they could support a peace process.
He said Poland would always stand for peace, but not at the price of capitulation, and would argue for a just settlement that respected borders and national sovereignty.
According to Tusk, Hanoi held a similar view on the issue.
Among the practical outcomes, the two governments signed agreements on education and tourism.
The number of scholarships for students and researchers from both countries will rise from 20 to 50.
On visas, the two leaders discussed further easing for Poles, with Hung indicating that Vietnam would consider visa-free travel.
The Polish airline LOT plans to launch direct Warsaw-Hanoi flights in the first quarter of 2027.
Tusk is due to attend a business roundtable on Monday and to meet Vietnam’s President and Communist Party General Secretary To Lam, and the head of the National Assembly, Tran Thanh Man.
(ał)
Source: PAP