Karel's uncle from the van der Hucht family obtained work at a tea company, and his father became the administrator of the Bolang coffee estate near Buitenzorg.

His father soon died, after which Karel was educated at home in Batavia in 1845, together with the children of Jan Jacob Rochussen, the Governor-General of the Dutch East Indies from 1845 to 1851.

In 1846, Karel Holle was appointed clerk at the residential bureau in Tjiandjoer (Cianjur) in West Java.

In 1865, he rented a parcel of uncultivated land on the northern slope of Mount Tjikoerai (Cikurai), about 13 kilometers south of Garoet (Garut) in Preanger (Parahyangan).

[1] Due to his knowledge and interest in working with the local Sundanese people, he was appointed as an unpaid government advisor.

[2] Holle was against what he called "fanatical" Islam, and believed Muslims should be free to fulfill their religious obligations, but with separation of religion and politics.

The vocabulary lists that he designed for distribution and elicitation around the Dutch East Indies continued to be collected into the 1930s, long after his death in 1896.