He worked in the Wrocław section of the Cultural Society of the Union of Jews in Poland and took a leading role in the dramatic circle forming in the city.

He wrote about Jewish life in Poland for the Yiddish press, literary sketches, and eventually a play, פּראָפעסאָר שוואַרצשטיין (Professsor Szwarcsztajn), and wrote a new version of the classic Yiddish play הערשעלע אָסטראָפּאָלער (Hershele Ostropolyer), which became a standard part of the State Yiddish Theater’s repertoire. At left is a poster for the E.R. Kaminska State Yiddish Theater’s 1953 production of Hershele, or, as it was known in Polish, Herszełe z Ostropola.

In the late 1950s Zonszajn returned to Warsaw where he was secretary of Jidisze Szriftn and rediscovered his poetic talent, formulating his unique terse style in his collections וואָרט און ניגון (Word and Melody) in 1959 and יונגער ווינטער (Young Winter), which was published shortly after his death on February 7, 1963. He is buried in the Jewish cemetery at Okopowa Street in Warsaw.

Many of Zonszajn’s poems were translated into Polish and published in major Polish literary journals and collections. In the introduction to a Polish translation of Zonszajn’s collected verse, the writer Arnold Słucki noted that writers such as Zonszajn should, above all, be considered Polish poets, despite the fact that they wrote in Yiddish.