Marc leads the policy division in the Ministry of Health that is responsible for national training and development of healthcare professionals and manpower standards, together with the professional boards and councils. He is also the advisor for policy and systems in the Communicable Diseases Agency, providing guidance on areas such as vaccinations, pandemic preparedness planning and disease surveillance systems.

During the COVID-19 pandemic, Marc was initially seconded to the World Health Organization headquarters as technical lead for health emergency preparedness in cities and urban settings. Upon return, he was Director of the Contact Tracing and Epidemiology Centre, overseeing policy and operations for national contact tracing efforts, disease surveillance, epidemiologic investigations and data analytics. Post-pandemic, Marc led the reorganization, transition and expansion of public health functions in the new Communicable Diseases Agency.

A medical doctor and public health specialist by training, Marc obtained his Master of Public Health from the National University of Singapore. He is an adjunct Associate Professor with the School of Public Health at the National University of Singapore, the Lead for Pandemic Preparedness at the Asia Centre for Health Security, and a Fellow with the Academy of Medicine Singapore.