The poor physical health of patients with severe/chronic mental illness is now well‐known, yet little has been done to address the issue. Adverse medication effects, lifestyle, and social factors can all contribute to high morbidity and mortality rates when compared to the general population. To arrest poor physical health, a Wellness Clinic within a mental health hospital was developed to provide continuity of care when patients were discharged from the hospital. A retrospective, within‐subjects, quasi‐experimental, longitudinal time‐series study was conducted analysing the demographics and physical health parameters of 57 patients who remained with the service over a four and a half year time period. Assessments were taken at baseline, 12, 24, and 36 months for each individual. Despite increasing levels of psychotropic and other health medication over time, physical health parameters were generally held stable for most measures across the four time periods. HDL‐C levels were significantly improved between baseline and 36 months. This stability over time suggests that ongoing assessment, monitoring, and treatment is necessary to arrest the downward trajectory of poor physical health in mental health and opens the door for future research to invest in interventions to run alongside the Wellness Clinic and improve patient physical health.