Also known by the pen name Monsieur d'Amour, he wrote more than 200 short stories, novels, poems and stage plays during his career; he is also recorded as directing and/or writing eleven films.

[1] By an early age he had begun contributing to Chinese-owned newspapers; his first literary work, Tjerita Penghidoepan Manoesia (Stories on the Life of Man), was published in Sin Po in 1919.

[3] He wrote numerous stories for the Gresik-based publication Hua Po beginning in 1922, and in 1925 he helped establish the magazine Penghidoepan; he became its editor and writer of many of its contents in its early years.

[3] Njoo became active with the Miss Riboet's Orion troupe in the late 1920s, writing several of their stage plays,[2] including Kiamat (Apocalypse), Tengkorak (Skull), and Tueng Balah.

[12][14] The Japanese occupation of the Indies led to all but one film studio in the country being closed;[15] Njoo and Young went back to the theatre, joining the Bintang Soerabaia troupe.

[1] The Indonesian film historian Misbach Yusa Biran credits Njoo with helping Miss Riboet dominate the country's touring theatre industry from 1929 until 1931.

[4] This was echoed by the leftist Indonesian literary critic Bakri Siregar, who writes that Njoo and fellow dramatist Andjar Asmara's stage plays revitalised the genre in the Indies and made the works more realistic.