Introduction: Type 2 diabetes mellitus (T2DM) requires lifelong self-management through healthy lifestyle behaviors. While lifestyle modification is essential for glycemic control, many patients struggle to sustain these behaviors. Existing evidence has largely focused on behavioral adherence and clinical outcomes, with limited attention to patients' lived experiences, particularly in Indonesia. This study explored the lived experiences of adults with T2DM in maintaining healthy lifestyle behaviors using a descriptive phenomenological approach. Methodology: Fifteen adults with T2DM were purposively recruited from primary healthcare centers and outpatient diabetes clinics in Makassar, Indonesia. Data were collected through semi-structured, in-depth interviews and analyzed using Colaizzi's seven-step method. Trustworthiness was established through member checking, reflexive documentation, audit trails, and rich contextual description. Results and Discussion: Six themes emerged: (1) emotional responses after diagnosis, including shock and fear; (2) acceptance and adaptation through self-awareness and resilience; (3) transformation of daily behaviors—diet, physical activity, medication adherence, and glucose monitoring; (4) challenges from occupational demands, financial limitations, cultural food practices, and psychological distress; (5) the role of family, healthcare professionals, and peer support; and (6) evolving meanings of healthy living as responsibility, independence, and improved quality of life. Findings show that maintaining healthy behaviors is a dynamic process of emotional adaptation and meaning-making rather than mere compliance. Conclusion: Sustainable diabetes self-management is shaped by emotional experience, social relationships, and cultural context, and strengthened by family support and individualized, culturally responsive care.