Aris Servetalis, a popular actor who starred in Ionesco's 1959 absurdist play Rhinoceros, announced he was stepping down in an Instagram post late on Tuesday.
The Kivotos theatre said the production was postponed momentarily.
"I cannot support the segregation of people imposed by the new measures," wrote Servetalis, who has voiced scepticism over the effectiveness of COVID-19 vaccines.
"We are a society of individuals, not a herd divided between vaccinated and not."
Aris Servetalis
His decision drew a firestorm of criticism from across the entertainment world, which has been hard hit by several lockdowns since the pandemic began after already suffering during years of economic crisis.
"I am shocked," said Spyros Bibilas, who heads the Greek Actors' Association.
"I did not expect an actor to stop a show, ignoring that other people work there too. I find it unacceptable."
Development Minister Adonis Georgiadis tweeted his dismay, saying: "Are these reasons for leaving his colleagues unemployed because he is not getting his way in the country?"
Responding to the criticism, Servetalis said he had informed the theatre company and the director in July of his intentions to leave if such measures were taken, allowing them time to find a replacement.
Thousands of Greeks took to social media to congratulate Servetalis.
Protests against vaccinations drew crowds of thousands this summer.
"It was about time someone said NO," one Instagram user wrote below the actor's post.
"I bow to your ethos and integrity," another said.
In Rhinoceros, Servetalis played the central character Berenger, the only resident of a provincial French town who does not turn into an animal.
Theatre of the Absurd pioneer Ionesco had called it an anti-Nazi play.
Prince Nikolaos de Grece and Chrysi Vardinoyannis have officially announced their engagement, with a wedding…
A Greek woman was arrested by the occupying authorities in Cyprus after attempting to smuggle…
Mimis Domazos, one of Greece's greatest football legends, has passed away at the age of…
Two gynecologists accused of involvement in an illegal adoption ring in Chania have been released…
The monks stated that the persecution of the Ukrainian Orthodox Church continues with unrelenting intensity.…
Energean, a British-Greek oil and gas company, announced on Thursday that it has finalized a…