This chapter discusses the necessity of strategies and policy integration for achieving decarbonization across the entire East Asian region. In response to challenges such as climate change, resource depletion, and social inequality, it proposes a framework for building a sustainable society based on five core principles: low-carbon, circular, ecological, safe and secure, and smart. These principles are mutually reinforcing and serve as a foundation for the design of decarbonization policies and institutional reforms. A comparative analysis of CO₂ emission pathways in China, Japan, South Korea, and the United States reveals differences in the relationship between economic development and emissions reduction, as well as varying degrees of progress in decarbonization. In particular, China is projected to reach its carbon emissions peak at a per capita GDP of around 40,000 international dollars (PPP-adjusted), similar to advanced economies, raising concerns about a potential “medium-carbon trap.” Balancing future economic growth with decarbonization will be a key issue. Achieving sustainable, region-wide decarbonization will require cross-border policy coordination and a structural transformation of society as a whole.