It was hard to imagine a more potent sign of the healing of Europe's post-war scars.
Past presidents of the European Council have always been high-ranking officials, such as former heads of government.
She added that Mr Tusk was not impartial.
Hours after the letter was circulated, Tusk said at the news conference that he is "responsible for European values and principles".
The leaders voted 27 to one to give him another two-and-a-half-year term.
Instead, Mr Tusk found his home country blocking the path, and a Polish political psychodrama imported to Brussels.
Kaczynski also insisted that "Germany's current dominance of the European Union is an artificial situation resulting from economic relations and the incredible opportunism of elites in Brussels".
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"The lesson for the future is that we have to avoid at all cost a situation in which one country could have veto over everyone else", a senior diplomat in Brussels said. This may be a reference to a speech Mr Tusk made in Wroclaw previous year that called on the government to "respect the people, the principles and values of the constitution".
Centrist Tusk has been a long-term foe of the head of the conservative Law and Justice party, Jaroslaw Kaczynski, who has accused him of "moral responsibility" for his twin brother's death in a plane crash in Russian Federation in 2010.
Szydlo made no threats to block the vote or the summit. Poland responded to Tusk's re-election by blocking the summit's final statement. One EU source said it is "doubtful" the Commission will introduce more legislation to limit the gender wage gap, but that the executive could recommend measures for countries with particularly big differences in average pay between men and women.
Most EU nations want quick approval of Tusk since the EU is already facing so many issues that a drawn-out succession process would further damage the bloc. What explains the government's hostility?
Tusk said on Wednesday he was "ready for this judgement" by the 28 leaders but rejected criticism by Poland's prime minister Beata Szydlo that he had "brutally violated" his job's supposed political neutrality. Kaczynski accuses Tusk of contributing, through lax security, to the death of his twin, President Lech Kaczynski, in a plane crash in 2010. Hungary's prime minister Viktor Orban, an ally of Mr Kaczynski, approved Mr Tusk. "It's time for some politicians to understand this".
"Some people would say we have failed, but no: we have shown that Poland matters", said Mr Kaczynski.
In reaction, Civic Platform leaders expelled Saryusz-Wolski from the party.