Koun was born in Bursa, Ottoman Empire to a Greek mother and a Polish Jewish father.
[1] Koun gave premieres in Athens of works by avant-garde European playwrights such as Bertolt Brecht and Luigi Pirandello.
She played Blanche Dubois in A Streetcar Named Desire which was staged by Koun's Art Theater.
[2] Other playwrights that Koun introduced to Greek audiences include Jean Genet, Federico García Lorca and Eugène Ionesco.
Koun collaborated with famous Greeks like Manos Xatzidakis, George Bakalo, Odysseas Elytis, Giannis Tsarouxis, Rallou Manoy, Basilis Rotas, Zouzou Nikoloudi, Maria Kynigou Mikis Theodorakis.