De Jong studied history and social geography at the University of Amsterdam. He worked as a foreign newspaper correspondent from 1938 until 1940. He wrote on 31 August 1939 that an invasion of Poland would not escalate into war: "The Second World War has been averted for a long time [for the immediate future], probably for years", was printed on 2 September. He wrote on 6 April 1940 that there was no indication whatsoever that "Berlin thought of expanding the war [into other countries]".[1] After the German invasion of the Netherlands, De Jong managed to escape to London with his wife Liesbeth Cost Budde on 15 May 1940 on board of the Friso. He would work for Radio Oranje, broadcasting to the Nazi-occupied Netherlands..