His father, a bank manager, had a collection of books which Mihardja credited with sparking his interest in literature.

[2] In 1949, he published his most important work, Atheist, which centered on a Muslim man from West Java, Hasan, and his relationship with his friends, who had been influenced by foreign ideas, such as Marxism.

[4] Atheist was later adapted into a 1974 film, which was directed by Sjumandjaja and co-starred Christine Hakim and Deddy Sutomo [id].

[1] In 1950, he helped to found Lekra, an Indonesian writers' organization tied to the Communist Party of Indonesia.

He described the novel as his answer to issues raised in Atheist and its main message to be that "God made man to be His representative on earth, not that of Satan."