He was born in a family of Polish Jews to Michał Hertz and Paulina nee Turower.

Late 1937 he started living in Paris where he attended lectures on Écoles des Hautes Études Internationales.

[4] Hertz left no diaries or autobiographies, and in his interview Sposób Życia published in 1997 he posed as a heterosexual, old-fashioned misanthrope, never using the word "homosexual" in any context in the book.

Both became known to the Polish People's Republic authorities, up to a point of a delation archived in IPN explicitly calling Hertz homosexual and drawing attention to his relationship with Henryk Krzeczkowski.

Following years he published his poems in „Tygodnik Powszechny", „Nowa Kultura", „Kuźnica", „Więź", „Znaki czasu", „Zeszyty Literackie [pl]".

His closest friends included Jarosław Iwaszkiewicz, Czesław Miłosz, Zygmunt Mycielski, Antoni Sobański, Stefan Kisielewski, Julian Stryjkowski, Henryk Krzeczkowski [pl]; he kept in touch with the staff of Paris' "Kultura" – incl.

In 1957 he was one of the initiators and members of the editorial board of the monthly "Europa" (the magazine was suspended by the authorities before the first issue was published).

Kazimiera Iłłakowiczówna, Jan Kasprowicz, Zygmunt Krasiński, Teofil Lenartowicz, Juliusz Słowacki).

He has been awarded many times for his translation work, which included translating Anna Achmatowa, Joseph Brodsky, Jacob Burckhardt, Anton Chekhov, Fyodor Dostoevsky, Hugo von Hofmannsthal, Pavel Muratov, Marcel Proust, Ivan Turgenev.