With nearly all ballots counted in the run-off vote, Zelensky had taken more than 73 percent with incumbent Petro Poroshenko trailing far behind on 24 percent.
The new president has no previous political experience and is best known for starring in his own Ukraine comedy television show where, ironically, he plays the role of the country’s president.
German Greens MEP Rebecca Harms, who led the European Parliament’s election observation delegation in Ukraine, said, “Parliament encourages and supports the incoming president in continuing, and strengthening reform efforts, particularly in fighting corruption and poverty. We are confident that the incoming president is fully aware of his responsibilities.”
She added that in carrying out these reforms “he can fully rely on the support of the European Union.”
Harms said, “The president-elect of Ukraine can count on the European Union strong support on the country’s reform path and its sovereignty, independence and territorial integrity”.
“The reform agenda should be carried out in close cooperation and good faith with all other state institutions, notably the Verkhovna Rada. Ukrainian citizens have given the new president a strong mandate with an overwhelming vote. This result could also read as a serious reform appeal to the Verkhovna Rada,” she added.
Donald Tusk and Jean-Claude Juncker both pledged to continue their "steadfast support" for Ukraine's sovereignty.
“As President of Ukraine, you can count on the EU's strong support to Ukraine's reform path, including consolidating the rule of law, fighting corruption, maintaining macro-financial stability and pursuing the essential reform of the energy sector” Donald Tusk
Tusk, president of the European Council, congratulated Zelensk, telling him, “Allow us to express our appreciation for the strong attachment to democracy and the rule of law that the people of Ukraine have demonstrated throughout the electoral process.”
“This is a major achievement in the complex political, economic and security environment, against the backdrop of continuous challenges to Ukraine's territorial integrity.”
“Significant progress has been made in the five years since Ukraine's Revolution of Dignity, and much remains to be accomplished to fully realise the peaceful, democratic and prosperous Ukraine that its citizens have called for.”
Tusk’s letter went on, “As President of Ukraine, you can count on the EU's strong support to Ukraine's reform path, including consolidating the rule of law, fighting corruption, maintaining macro-financial stability and pursuing the essential reform of the energy sector.”
“The president-elect of Ukraine can count on the European Union’s strong support on the country’s reform path and its sovereignty, independence and territorial integrity” Rebecca Harms MEP
German Chancellor Angela Merkel, meanwhile, hinted as much in a congratulatory statement to Zelensky, while extending the 41-year-old president-elect an invitation to Berlin.
"The stabilization of Ukraine and peaceful conflict resolution are as important to me as the implementation of centralised judicial reforms, decentralisation and the fight against corruption," Merkel said.
Kyiv's pursuit of closer ties with the West and the EU was the trigger for Ukraine's ongoing conflict with Russia, which developed into a war along the border that led to Moscow's annexation of the Crimean Peninsula, as well as its incursion into Ukraine's separatist eastern provinces, in 2014.
The EU imposed sanctions on Moscow as a result.