Background: The growing burden of chronic disease (CD) in Ireland represents the greatest challenge to Irish Health Services. The role of physical activity/exercise training (PAET) is well established as an adjunct therapy in the management of CD. An integrated multi-disease, community-based exercise programme (MCEP) has the potential to offer a resource-efficient strategy to provide exercise in the community for either those with CD following completion of medically supervised hospital-based programmes or for individuals who do not require medical supervision. The purpose of this PhD was to assess the adherence to, efficacy of and patient perspective of a MCEP. A total of 118 patients with coronary artery disease (CAD) who had completed hospital-based cardiac rehabilitation, along with individuals with other CD (OCD), were referred by health care professionals to a newly established MCEP. CAD patients who could not attend the MCEP were assigned to a control group (CAD-CG) that received usual care advice. Study 1 evaluated baseline characteristics of individuals with CAD (96, 73%M) to those with OCD (98, 47%M) and a CAD-CG (22, 77%M) and compared rates and predictors of adherence to the MCEP. Outcome measures were socioeconomic and health-based demographics, health indices, functional capacity, and health-related quality of life (HRQoL). There was a significant difference in age, gender, number of comorbidities, and certain medications/conditions between the groups. Individuals with CAD had significantly better functional capacity and HRQoL scores than individuals with OCD. Females and individuals with lower mental wellbeing were less likely to attend and more likely to drop out. Study 2 evaluated the efficacy of participation in a MCEP for 10-weeks on selected health indices, functional capacity, and HRQoL. Lower body muscle strength increased (p < 0.005) in both CAD and OCD compared to CAD-CG. Within group improvements were found in aerobic fitness (p < 0.005) and waist circumference (p < 0.05) in both CAD and OCD, while upper body strength (p = 0.003) and perceived physical (p = 0.013) and mental health (p = 0.003) improved in OCD only. Study 3 explored CAD patient experiences of participation in a MCEP and dimensions influencing their physical activity engagement. Twenty-four individuals (63% M) who completed the initial 10 weeks of the MCEP attended a focus group, analysed using inductive thematic analysis. Main themes identified included ‘moving from fear to confidence’, ‘drivers of engagement’, ‘challenges to maintaining exercise adherence’ and ‘life beyond their illness’. Conclusion: An integrated MCEP was found to be a safe, effective, and acceptable setting for improving or maintaining actual and perceived physical, and mental, wellbeing in individuals with CD. Females and individuals with lower mental wellbeing should be supported to encourage adherence.