Through five case studies, the Ports of Rotterdam, Los Angeles, Singapore, Vancouver, and Piraeus, this thesis investigates how green ports influence sustainable supply chain management. The study finds various strategic paths to green port development, including thorough transformation, technology-driven innovation, market-based incentives, cooperative stakeholder involvement, and resource leveraging. Common success elements across these instances are integrated governance systems, public-private partnerships, technological adaptation, phased implementation with defined milestones, and thorough performance measurement. The research shows how green ports support sustainable supply chain management by means of environmental impact reduction, supply chain optimization, and stakeholder cooperation. Drawing on these results, the thesis offers strategic advice for port authorities, legislators, and maritime industry stakeholders to hasten the change toward more sustainable port operations. The study finds that ports can be strong catalysts for sustainability change across maritime supply chains, therefore proving that environmental stewardship and economic success can be sought concurrently.