Adjunct Associate Professor Firth completed his BDS undergraduate training at the University of Adelaide in 1983 and postgraduate training in Oral Pathology and Oral Medicine at the University of Melbourne in 1988. He was a reporting oral pathologist for the Oral Pathology Diagnostic Service, University of Melbourne and consultant in Oral Pathology for Melbourne Pathology. He was awarded Fellowship in the Faculty of Oral Pathologists, Royal College of Pathologists of Australasia and subsequently awarded a Fellowship with the Faculty of Oral and Maxillofacial Pathology for forensic odontology in Australia, New Zealand and Thailand. In 1998 he moved to New Zealand and was a consultant oral pathologist for Medlab Dental and Oral Medicine Consultant with the University of Otago. He was Associate Professor in Oral Medicine and discipline Lead and Program Convenor Oral Medicine and Oral Pathology, University of Western Australia, a member of the Oral Oncology Research Group after returning to Australia in 2016. His research interests include oral cancer and immune mediated oral mucosal diseases. He joined the University of Queensland in 2018 taking up a position as Associate Professor in Oral Medicine. In 2020 he was appointed Senior Oral Medicine Specialist at Metro South Oral Health and is currently consultant oral pathologist with Clinipath (WA) and Sullivan Nicolaides Pathology (Qld).