PHEinAction® is a theory-based nurse-led patient engagement intervention developed among an Italian older adult population with various chronic diseases to facilitate cognitive, emotional, and behavioral processes in promoting individuals' active roles. This study aims to adapt and evaluate the effectiveness of PHEinAction® on diabetes self-management (DSM) among Turkish type 2 diabetes mellitus patients. First, the generic content of the intervention was customized for diabetes management and adapted for the Turkish population, including back-forward translation and expert panel evaluation; then, a randomized controlled trial was conducted with 51 adult diabetes patients randomly assigned to intervention or the control group receiving the usual care. The intervention consisted of two in-person sessions of 4-week intervals, a telephone consultation, and home-based written exercises, which involved personalized care activities addressing individuals' engagement levels and covering the cognitive, emotional, and behavioral aspects. The scores for treatment adherence, self-efficacy, and patient engagement had significantly improved with a large size effect in the intervention group at the fourth-week follow-up compared with the control group. Findings suggest that the nurse-led personalized patient engagement program could effectively promote DSM.