Kho Tjoen Wan was born in the early twentieth century into a poor Chinese family in Brebes, Central Java, Dutch East Indies.

[2][3] By age 10 he left Brebes for the capital Batavia, where he started work as an assistant at Perniagaan, a Chinese-owned Malay language paper with a conservative ideology.

[2] During the 1910s, a period which saw the rise of the Sarekat Islam and other radical movements in Java, Kho became increasingly attracted to left wing and anticolonial politics.

[4] The book, which criticized the controversial proposal for a conscript army of Indies natives, earned him a 3 month jail term in 1917 under the strict Dutch censorship laws.

In 1917, after he was released from jail, he left Batavia and returned to Brebes, where he founded a new chapter of the Tiong Hoa Hwee Koan (a Chinese Indonesian education and self-improvement organization).

[13][14] In 1921 the Communist Party of Indonesia (PKI) was founded; Kho, who knew its leaders from his time working at Sinar Hindia, joined it at some point during its early years.

[19] He was also active in other left-wing organizations in the city; he was treasurer of the Sugar Worker's Union (Perserikatan Kaoem Boeroeh Goela) and commissioner of a miner's group (Koempoelan Tambang), and sat on an inter-ethnic respect committee (Comité Kehormatan Bangsa).