Ash completed his PhD in 2002, on Salmonella pathogenesis with Prof Gordon Dougan at Imperial College, London. During his first post-doc at the London School of Hygiene & Tropical Medicine, he examined cellular immune responses to the gram-negative PC3 bacterial pathogen, Burkholderia pseudomallei. In 2006, Ash moved to QIMR, Brisbane, to study cellular immune responses to protozoan parasites, Leishmania and Plasmodium. He received his first NHMRC grant in 2010 and started his own lab at QIMR Berghofer in 2012 as an NHMRC Career Development Fellow. In 2020, he moved his lab to The Doherty Institute and Department of Microbiology and Immunology, University of Melbourne. His current interests are to employ single-cell genomics and computational approaches to examine T and B lymphocyte biology in experimental and clinical settings.