OBJECTIVES Physical activity (PA) and exercise is increasingly being recognised as an efficacious component of treatment for various mental disorders. The association between PA and cardiometabolic disease is well established, as is the strong link between mental illness, sedentary behaviour and poor cardiometabolic health. Examples of successful integration of clinical PA programs within mental health treatment facilities are increasing. The aim of this review was to summarise the evidence regarding PA and mental illness, and to present examples of clinical exercise programs within Australian mental health facilities. METHODS A narrative synthesis of systematic reviews and clinical trials was conducted. RESULTS Evidence supporting the inclusion of PA programs as an adjunct to treatment for various conditions was presented; including depression, schizophrenia, anxiety disorders, post-traumatic stress disorder and substance abuse. In light of the available evidence, the inclusion of clinical PA programs within mental health treatment, facilitated by dedicated clinicians (exercise physiologists / physiotherapists) was justified. CONCLUSIONS PA is a feasible, effective and acceptable adjunct to usual care for a variety of mental disorders. There is a clear need for greater investment in initiatives aiming to increase PA among people experiencing mental illness, given the benefits to both mental and physical health outcomes.