Mark studied Microbiology at the University of Surrey where he also carried out his PhD in Virology. Following a first postdoctoral position at the University of Southampton studying the immune response to cancer, he moved to the University of Cambridge in 1993 to the Department of Medicine. There he started his work on viral immunology, becoming a principal investigator.
Mark has an active research group of PhD students and postdocs focused on understanding the immune response to persistent viruses. Mark is also the Departments Biological Safety Officer and chairs the Universities Biological Safety sub-committee. He is an Editor of the Journal of General Virology and acts as external examiner at the University of Surrey on an MSc course in Medical Microbiology. He is a member of the Microbiology Society and the British Society of Immunology.