In 1947, Bjerre embarked on a lifelong career as a freelance journalist by going to South Africa, where he lived among the San bushmen and studied their culture and customs.
The following year, he returned and shot the documentary movie Kalahari, which gives an insight into the lives and rituals of this ancient people.
Jens Bjerre wrote five books about his travels and encounters with primitive people, which have been translated into 15 languages.
Bjerre conducted scientific expeditions to the Kalahari Desert and the interior of Australia in collaboration with the Royal Geographical Society in London and the National Museum in Copenhagen.
He collected cultural artefacts among tribal people in New Guinea for the Danish National Museum, and lectured on universities and museums throughout the world, among them Harvard, Yale, Stanford and National Geographic Society in Washington and the Royal Geographical Society in London.