The primary aim of this study was to test the causal structure of the model of therapeutic engagement (MTE) for the first time, to examine whether the model assists in understanding the process of patient engagement in cardiac rehabilitation (CR) programs. This study used a prospective design, following up patients from the Gold Coast University Hospital Cardiology ward who attended Robina Cardiac Rehabilitation Clinic. A structural equation model of the interactions among the proposed variables within the three stages of the MTE (intention to engage in CR programs, CR initiation, and sustained engagement) revealed significant relationships among these variables in a dataset of 101 patients who attended a CR program. However, no relationship was discerned between outcome expectancies and patient intention to engage in CR. Patients’ willingness to consider the treatment also mediated the relationship between perceived self-efficacy and patient intention to engage in CR. These findings help clarify the process proposed by Lequerica and Kortte (2010) in the context of patient engagement in CR programs. The findings also reveal information on how patients engage in CR programs. Importantly, this provides new information for healthcare providers, enabling them to more effectively engage patients according to their stage of engagement.