Koning was also a prolific journalist, contributing for almost 60 years to many periodicals including The New York Times, International Herald Tribune, Atlantic Monthly, The Nation, Harper's, The New Yorker, and De Groene Amsterdammer.

As an editor of De Groene Amsterdammer, a Dutch weekly, 1947–50, he was invited to run a cultural program on Radio Jakarta, Indonesia which he did from 1950-51.

During the Vietnam War he turned his attention to protest, helping to found the still-active 'RESIST' organization in Cambridge, Massachusetts, with Noam Chomsky among others.

Four of his novels were made into films: A Walk with Love and Death, which was Anjelica Huston's first film, directed by her father, John Huston; The Revolutionary, starring Jon Voight; Death of a Schoolboy, for BBC London, and The Petersburg-Cannes Express.

(Until 1972 writing under the name Hans Koningsberger) Many of his novels have also been published in other countries including England, the Netherlands, Spain, France, Italy, Germany, and Japan.