People with spinal cord injury (SCI) who live with chronic pain report poorer mental health (e.g. depression and anxiety symptoms) than those without disability. Poor mental health can further limit social participation (including employment) and physical functioning, and increase the use of health care services. Therefore, there is a need for safe, accessible, and affordable strategies to improve pain and mental health in this population. Exercise may be an effective strategy, but it’s not known if people with SCI living with chronic pain also benefit. Forty-two adults with SCI reporting chronic pain will receive a personalized exercise prescription and weekly exercise counselling. An equal group will go on a waitlist. After six months, we will test for differences in mental health between the groups, and if changes in fitness, pain or social factors can explain these differences. We will interview participants to gather their perspectives on the program, and what we can do better to improve mental health. This study will be the first to test if exercising improves mental health, how much exercise is needed, and the processes by which exercise may improve mental health in people living with SCI and chronic pain.