Mr Zelensky has no political background, but plays the president in Servant of the People, a popular TV show in which his character, a former history teacher, wins the presidential election after a video of him condemning governmental corruption goes viral.
The political newcomer is reportedly being backed by Igor Kolomoiski, the Jewish-Ukrainian billionaire. Mr Poroshenko, himself worth hundreds of millions, derisively described Mr Zelenskiy as “Kolomoisky’s puppet.”
Under the Ukrainian political system, if no candidate secures a majority of the vote, the contest proceeds to a run-off between the two leading candidates, with this expected to take place on April 21.
Mr Zelensky said he was happy with the results but that “this is only the first step toward a great victory.”
Meanwhile, Mr Poroshenko described his disappointing result as a “tough lesson” and said there was a need for “serious work to correct mistakes made over the past years.”