Dr Doctor (Doctor ). de Jong studied medicine at the University of Amsterdam, completing his doctoral dissertation on HIV treatment in 1996. Before joining RIVM, he headed the department of Medical Microbiology and Infection Prevention at Amsterdam UMC, following from his role in the same position at the former AMC and VUmc before the academic hospitals merged. He also spend a number of years as head of Virology at the Oxford University Clinical Research Unit in Ho Chi Minh City, Vietnam.

In 2007, he was appointed professor of Clinical Virology at the University of Amsterdam. In addition to his job at RIVM, De Jong is still affiliated with Amsterdam UMC, spending one day a week as a professor at the medical centre.