Due to his lineage from his father's side, he was subjected to antisemitic discrimination during the successive fascist governments of World War II Romania.

Between 1919 and 1929, he attended Spiru Haret High School [ro] in Bucharest, where, despite his background, he was instructed in religion by a Christian priest.

In 1939, Steinhardt worked as an editor for Revista Fundațiilor Regale (a government-sponsored literary magazine), losing his job between 1940 and 1944, due to antisemitic policies, first under the Iron Guard regime (the National Legionary State), and then the government led by General Ion Antonescu.

From 1948 until 1959, he experienced a new period of persecution, this time from the Romanian Communist regime, during which non-communist intellectuals were deemed "enemies of the people".

As a consequence, he was accused of "crimes of conspiracy against social order", he was included in the "group of mystical-Iron Guardist intellectuals", and sentenced to thirteen years of forced labor, in Gulag-like prisons.

[2] The first manuscript of Jurnalul Fericirii ("The Happiness Diary") was confiscated by the Securitate in 1972, and restituted in 1975, after an intervention by the Association of Writers (Asociatia Scriitorilor Bucuresti).

In the end, Steinhardt had written and edited several different versions, one of which had reached the expat writers and dissidents Monica Lovinescu and Virgil Ierunca in Paris.