[2] Hein ter Poorten was born on 21 November 1887 in Buitenzorg (now Bogor) on Java, which was at the time part of the Dutch East Indies.

He was the son of Franciscus Hendricus ter Poorten, a chief mate in the Government Navy, and of Clasina Ambrosina Kater.

[1] After having been sworn in as an artillery officer in 1911, he helped to found the army air force, and in 1919 began a course at the Hogere Krijgsschool staff college in the Netherlands.

Ter Poorten was regarded by his contemporaries in the army as a skilled commander with a firm understanding of military affairs in the East Indies, and thus was able to get on well with his subordinates and fellow officers; his relations with the civilian administration were less successful.

By March, Ter Poorten became the de facto head of all Allied forces on Java, following rapid Japanese advances and the break-up of ABDACOM.