This research explores the transformative role of Emotional Intelligence (EI) in promoting sustainable social development through social work practice. Rooted in empathy, self-awareness, self-regulation, motivation, and social skills, EI equips social workers to engage effectively with clients in emotionally complex contexts such as poverty, trauma, addiction, and marginalization. Drawing on foundational theories and contemporary studies, the paper demonstrates how EI enhances practitioners' capacities for communication, advocacy, conflict resolution, and culturally sensitive practice. A detailed case study of a social worker named Selvi illustrates EI in action, showcasing how emotionally intelligent interventions can foster community trust, drive collective action, and achieve lasting social change. The research aligns EI competencies with the United Nations Sustainable Development Goals, particularly Goals 3 and 10, emphasizing EI’s relevance in addressing systemic inequities. It concludes by recommending the integration of EI training into social work education to build emotionally resilient professionals capable of sustaining ethical and impactful development outcomes.