The article analyses the evolution of environmental protection in Italian and European administrative law, with particular reference to the introduction and application of Minimum Environmental Criteria in public procurement. It describes the transition of public administration from a mere supervisory role to an active promoter of sustainability through binding instruments such as green public procurement and the Minimum Environmental Criteria, framed within a broader normative context that includes recent provisions of the Public Contracts Code and the strategies of the National Recovery and Resilience Plan. Particular attention is given to the role of Article 3-quarter of the Environmental Code as a fundamental rule that requires the integration of the sustainable development principle in every administrative activity, including procurement procedures. The jurisprudential analysis highlights interpretive controversies concerning the immediate appealability of tender notices that omit or generically reference the Minimum Environmental Criteria, revealing a strict orientation aimed at ensuring transparency, certainty, and respect for the principles of fair competition and environmental protection. The study concludes by proposing a model of participatory and integrated environmental governance, which establishes sustainability as an overriding transversal principle of public contracts, laying the foundation for the full implementation of sustainable development goals and eco-compatible innovation.