Microplastic pollution has emerged as a defining socio-ecological crisis of the Anthropocene, transcending its initial classification as a marine litter problem to become a complex, global threat embedded in Coupled Nature–Society Systems (CNSS). This review synthesizes current knowledge on the origins, pathways, impacts, and governance of microplastics (MPs), adopting a CNSS framework to highlight dynamic feedbacks between environmental degradation and human activity. MPs originate from both primary and secondary sources and disperse through atmospheric, terrestrial, aquatic, and biological routes, accumulating across trophic levels and global geographies. Their ecological impacts include biodiversity loss, ecosystem disruption, and bioaccumulation, while their socioeconomic consequences span food insecurity, health risks, economic loss, and cultural erosion - especially in low - and middle-income countries (LMICs). The paper advocates co-management as a systemic, adaptive governance strategy, promoting shared responsibility among states, industries, communities, and scientists. By integrating circular economy principles, extended producer responsibility, and One Health approaches, co-management enhances resilience and equity within CNSS. The review concludes with research priorities and policy recommendations, emphasizing the need for interdisciplinary collaboration, context-sensitive governance, and globally binding agreements to mitigate microplastic pollution across the plastic life cycle.