The Polish Law and Justice (PiS) party leader Jaroslaw Kaczynski said the wide backing for Tusk - even from Poland's allies in central Europe - was a result of pressure from the German government.
Poland accused Germany of forcing its will on the European Union on Thursday, in protest at the re-election of the bloc's President Donald Tusk, a Pole and political rival to whom Warsaw's rightwing government is staunchly opposed.
The former Polish prime minister thanked European Union leaders for their support following a controversial campaign for the top job.
Slovakia supports re-election of Donald Tusk as European Council President, Slovak Prime Minister Robert Fico said Wednesday.
As leader of the European Council he heads the body that groups the 28 national leaders of the EU, and hosts Brussels summits.
Support for Tusk was also voiced by German Chancellor Angela Merkel and French president Francois Hollande, who see in a vote for Tusk a vote for continuity and stability.
After being confirmed as president again, he tweeted: "Grateful for trust & positive assessment by #EUCO (European Council)".
Szydlo said the other European Union countries had ignored Poland's valid reasons to oppose Tusk's re-election. "We now have to work them to solve [this problem]".
Jarosław Kaczyński (C) is the leader of the ruling party in Poland.
Mr Tusk was reappointed despite a Polish plot to oust him from the role.
PiS leader Jaroslaw Kaczynski holds Mr Tusk politically responsible for the 2010 plane crash in Russian Federation which killed his twin Lech Kaczynski, and all other 95 people on board.
According to Tusk, one of the key summit objectives will be on jobs, growth and competitiveness while the benefits of "widely and fairly" spread economic growth will also be stressed.
"My position is very clear, I won't accept the summit conclusions, so the summit won't be valid", a visibly embittered Szydlo said.
"We knew this would happen", Prime Minister Joseph Muscat told reporters. Muscat said a more equitable spreading of posts would need to be addressed some time over the coming months.