Justin's research has primarily been conducted in sub-Saharan Africa, including South Africa, where his PhD research and postgraduate projects were undertaken, and in Zimbabwe, where his more recent research has been situated. Between 2011 and 2017, Justin worked with a research institute called the South African Tuberculosis Vaccines Initiative (SATVI), which runs TB vaccine trials in the Western Cape. Justin’s PhD thesis explored the effects of these trials on health seeking and delivery, care relations (especially between nurses and patients) and people's attempts to live healthy, moral, and respectable lives in a context of profound social and economic marginalisation.

Since joining LSHTM in 2017, Justin’s research has been primarily in the fields of antimicrobial resistance and multimorbidity. As part of the AMR Centre and the Anthropology of AMR Research Group, Justin has been involved in a range of research, public engagement, and capacity building projects, most notably as social science coordinator of the FCDO-funded FIEBRE study in Africa and Asia, and as co-investigator on a Wellcome Trust study examining the effects of mass typhoid vaccination on antimicrobial prescribing in Harare.

More recently, Justin’s work has turned to chronic disease and specifically the rising global concern with multimorbidity. Between 2021-2024, supported by a Wellcome Trust Research Fellowship and in collaboration with the Organisation for Public Health Interventions and Development (OPHID), the KnowM study developed a cross-disciplinary framework for conceptualising and responding to multimorbidity in Zimbabwe. As part of this fellowship, Justin co-established both the LSHTM Multimorbidity Interest Group within the Centre for Global Chronic Conditions and the Africa Multimorbidity Alliance. Continuing the momentum started during KnowM, the OptiMuL study (supported by a Wellcome Career Development Award) has established a multimorbidity learning hub in Zimbabwe to support the Ministry of Health and Child Care to develop critical, strategic 'in-house' learning capacities to respond to multimorbidity in a context of rapidly shrinking global health funding and technical support. Synergising with this work, Justin sits on the steering committee for Zimbabwe's newly-established National Public Health Institute, the MoHCC technical working group on NCDs, and co-Chairs the development of Zimbabwe's National NCD Strategy.