Healthcare systems play a dual role: they protect population health but also contribute to climate change through greenhouse gas emissions, resource use, and waste, while climate change is simultaneously increasing pressure on healthcare services through extreme weather events and rising disease burdens. In Italy, efforts to improve environmental sustainability and resilience in healthcare are growing but remain fragmented, with no comprehensive national framework. This paper presents a roadmap to support the commitment to a more sustainable and climate-resilient healthcare system, developed through an iterative participatory process with members of a national network of professionals (SOSTERRETE), including a national workshop hosted by the Italian National Institute of Health, followed by structured discussions and two rounds of asynchronous consultation. Contributions were synthesised to define shared principles, strategic objectives, priority actions, best practices, and policy recommendations. The findings identify key gaps in current policy and propose four strategic objectives: setting clear targets to reduce healthcare emissions, integrating sustainability into health system planning and governance, improving tools to measure environmental impacts and climate risks, and promoting actions that deliver both health and environmental benefits. Priority actions include improving energy use and infrastructure, reducing waste and unnecessary care, strengthening supply chain sustainability, enhancing preparedness for climate-related events, training healthcare staff, and establishing systems to track progress and ensure accountability. Italy has the chance to move from isolated initiatives to a coordinated national strategy, embedding sustainability into system governance, financing, and evaluation to reduce environmental impacts while improving resilience, health outcomes, and equity.