Justin was born in Bellville, South Africa in 1974. After completing his PhD thesis on the PK of rifampicin, isoniazid, and pyrazinamide at the University of Cape Town in 2004 (following a BSc (Hons) and an MSc in the pharmacoeconomics of malaria), Justin moved to Sweden to join Uppsala University as a postdoctoral researcher, where he worked on modelling techniques for describing disease progression in acute stroke and a multiple-dose implementation of the transit absorption model, as well as developing tools for visual and numerical predictive checks. Justin began his industry career when he joined Novartis in Basel in 2006, where he provided pharmacometric support for projects in respiratory disease and oncology; at the same time, he played a central role in launching the DDMoRe consortium. Justin joined Exprimo in 2010, and while there, amassed considerable experience in a wide range of therapeutic areas and modelling applications before leaving to join the newly-founded Occams in late 2015. Justin lives in Germany.
Justin is the developer of the open-source NONMEM project management tool Census, has been a co-developer of Xpose, and co-led the team developing DDMoRe's workflow tool. He is currently part of the development team for a new nonlinear mixed-effects modelling tool, nlmixr2. Justin served as a member of the Board of Directors for the International Society of Pharmacometrics (ISoP) from 2016 to 2021 and served as President of the organization in 2019. He was active in the organisation of the PAGE meeting from 2013 to 2023.