This chapter provides case studies about artificial intelligence (AI) applications for personal responsibility within public health. It begins with new conceptual frameworks, PMCO-AI model (Personalized Motivation, Capability, and Opportunity empowered by AI), a new paradigm designed to structure AI-driven interventions that support individual health behaviors. The chapter explores several case scenarios: personalized risk management and prediction, tailored health education, and AI-powered behavioral nudging and coaching. This chapter introduces a new Policy-Aware Personalized Opportunity (PAPO) model, which is a framework that integrates contextual policy data into personalized AI solutions. The PAPO-Heatwave AI framework shows how AI can treat local policy environments as personalized opportunities to respond to heatwaves in climate change. This chapter provides a roadmap for students, researchers, and developers to explore and develop AI applications for personal responsibilities in public health.