Kartosuwiryo was born in Cepu, an oil-producing town in Central Java, the son of a minor government official.

While touring Malangbong, near Garut in West Java, Kartosuwiryo met and married the daughter of a local PSII leader.

In 1957, agents sent by Kartosuwiryo unsuccessfully attempted to assassinate Sukarno with a grenade attack during a primary school function at Cikini, Central Jakarta.

The declaration of martial law in 1957 and the establishment of Guided Democracy by Sukarno in 1959 proved to be a turning point for Darul Islam's fortunes.

Kartosuwiryo responded by declaring "total war" in 1961, in which Darul Islam guerrillas increasingly used terror tactics and banditry against civilians, further alienating the population.