The president of the European Council is elected by a qualified majority of the members of the European Council for two and a half years with the possibility of being re-elected for one more term.
"I'm grateful for trust and positive assessment by the European Council. I will do my best to make the EU better," Tusk said on Twitter.
The former Polish prime minister swore in as European Council chief in late 2014 to stay in office until May 31, 2017. His re-nomination was hampered by the current Polish authorities that accused Tusk of violating the international official's impartiality code and interfering in the country's internal affairs.
In addition, according to the Polish leadership, the very procedure for electing the chairman of the European Council is far from being perfect. Warsaw believes that candidates for this post should be nominated by the EU member states rather than a country that presides in the EU Council.