Sebastian published several novels, including Accidentul ("The Accident") and Orașul cu salcâmi ("The Town with Acacia Trees"), heavily influenced by French novelists such as Marcel Proust and Jules Renard.

[3] Although initially an apolitical movement, Criterion came under the increasing influence of Nae Ionescu's brand of philosophy, called Trăirism, which mixed jingoistic nationalism, existentialism and Christian mysticism, as well as that of the fascist and antisemitic paramilitary organization known as the Iron Guard.

In response to the criticism, Sebastian wrote Cum am devenit huligan (How I Became a Hooligan), an anthology of essays and articles depicting the manner in which For Two Thousand Years was received by the Romanian public and the country's cultural establishment.

Had I known it would have been destroyed immediately afterwards, it still would have hurt me had it been written...[5]Sebastian became known in Romanian literature mainly for his plays, such as Steaua fără nume ("The Star Without a Name"), Jocul de-a vacanța ("Holiday Games"), and Ultima oră ("Breaking News").

It records the mounting persecution he endured and documents the disdain former friends began showing him in Romania's increasingly antisemitic sociopolitical landscape.

A fundamental testimony of anti-Semitism in Europe prior to, and during, the years of World War II, the Journal has been compared to those of Victor Klemperer or Anne Frank.

In 2023, two researchers at the George Călinescu Institute of Literary History and Theory of the Romanian Academy discovered[10][11] a handwritten notebook containing a previously unknown part of Sebastian's Journal, covering the years 1930 and 1931, when the writer was living in Paris.

[13] In the 2000s, Sebastian's Journal gained a new audience in Western countries due to its lyrical, evocative style and the brutal honesty of its accounts.

[14] Sebastian's niece, Michèle Hechter, a French writer and translator, published in 2000 an autobiographical work titled M. et M. dealing extensively with her uncle's life and writings.