Professor van Oijen has led research groups at Harvard Medical School (USA), Groningen University (the Netherlands), and the University of Wollongong (Australia). He was an ARC Laureate Fellow (2015-2020) and an NHMRC Leadership Fellow (L2; 2021-2025). His primary research interests revolve around DNA replication and repair, with a focus on developing imaging approaches and integrating these with molecular biophysical approaches to understand how microbial systems copy and maintain DNA. In Wollongong he was the founding director of Molecular Horizons, a molecular life sciences institute, and led the establishment of major core facilities. At the University of Sydney, Professor van Oijen is responsible for the Faculty of Medicine and Health's research portfolio and for achieving its strategic and operational objectives.