He returned to the Netherlands in 1950 to act as senior research assistant (1950–1954) and continuing academic employee (1954–1956) at the Univ. of Leiden, working at the university's Sinologisch Instituut; in 1956, he became the first Chair of Tibetan and Buddhist Studies when the position was created at the Insituut Kern (the Indological institute at the Univ. of Leiden). In 1957, de Jong founded the "Indo-Iranian Journal" with Univ. of Leiden colleague F. B. J. Kuijper in 1957 in order to facilitate the publishing of scholarly articles in Indology. In 1965, he moved to Australia to become professor of Indology at the Australian National University in Canberra, a position he held until his retirement in 1986.