Dr Day is a Senior Lecturer and Clinical Psychologist in the School of Psychology at the University of Wollongong. He coordinates and teaches primarily into clinically oriented 4th year subjects 'Psychological Assessment' (PSYC416) and 'Psychological Intervention' (PSYC417), as well as offering clinical and research supervision to honours, masters and HDR psychology students. He researches and practices evidence based psychodynamic psychotherapy for treatment of personality disorders drawing on contemporary approaches including Transference-Focused Psychotherapy (TFP) and Mentalisation-Based Therapy (MBT). He is active in clinical practice through Northfields Psychology Clinic, and consults widely to promote effective clinical practice in the treatment of complex mental health conditions throughout the health service. He has a particular research and clinical focus on assessment and treatment of personality disorders, including narcissistic and borderline personality disorder.

He has authored more than 20 peer-reviewed journal articles, two book chapters, and a clinician treatment manual. His work has been recognised through several awards, including the APS Early Career Research Award (2025), the UOW Research Impact and Community Engagement Award (2021), and the Vice-Chancellor’s Award for Outstanding Achievement in Research Partnership and Impact (2018). His PhD thesis on the topic of narcissism received the Examiners' Commendation for Outstanding Thesis (2022). Prior to joining the academic staff, he was a Research Fellow with Project Air Strategy, contributing to research, teaching, and service development for personality disorder.

Dr Day serves on the Executive Committee of the Australasian Association for Research and Treatment of Personality Disorders (AART-PD), is a founding member of the Australian Chapter of the International Society of Transference-Focused Psychotherapy, and is an Editorial Board Member of the Journal of Psychotherapy Integration. He has secured competitive research funding exceeding $150,000 and collaborates with researchers and clinicians across Australia, the UK, Denmark, Canada, the USA, and Italy.