<p>Severe marine plastic pollution necessitates sustainable operational models for the corresponding circular economy. A primary challenge in achieving sustainability is the effective assignment and management of differentiated environmental responsibilities among stakeholders. This study addresses this gap by developing a differential game model to examine sustainable strategies within an integrated system of waste governance and circular economy transition. The model’s core mechanism involves formulating and analyzing three distinct operational scenarios based on environmental responsibility attribution: no responsibility, fisherman-only responsibility, and enterprise-only responsibility. The analysis investigates optimal strategies for waste collection and resource valorization within the recycling and remanufacturing sectors. Results demonstrate that blockchain technology deployment significantly enhances enterprise environmental reputation and market demand. Government price subsidies effectively motivate enterprises to raise purchase prices for marine plastic waste, thus promoting fisherman participation. Although the number of participating fishermen does not directly impact enterprise decision-making, their increased involvement enhances overall governance effectiveness. Moreover, the environmental responsibility of fishermen leads to improved governance outcomes, a stronger corporate environmental image, and increased market demand. Finally, enterprises assuming environmental responsibility offer higher purchase prices, aligning fisherman incentives and fostering mutually beneficial outcomes for all stakeholders.</p>