GreenDIGIT tackles the challenge of reducing environmental impact of digital research infrastructures (RIs), which account for a growing share of global greenhouse gas emissions due to their high energy consumption. As research becomes increasingly data-intensive, ensuring that digital infrastructures operate sustainably is essential to align with the European Green Deal and UN SDGs. GreenDIGIT responds to this challenge by developing an integrated framework that will enhance the sustainability of digital RIs throughout their entire lifecycle. GreenDIGIT focuses on three major areas: technology innovation, strategic policy development, and capacity building. It established a reference architecture for sustainable RIs, and developing new tools for monitoring, assessing, and optimizing energy efficiency, and minimizing carbon footprints in data centres, cloud infrastructures, and networking components. These solutions will be deployed across four major European digital RIs—EGI, SLICES, SoBigData, and EBRAINS—modelling the entire ESFRI research landscape. GreenDIGIT also prioritizes scientific workflow optimization, integrating Reproducibility as a Service (RaaS) to help researchers design energy-conscious digital applications while ensuring data and experiment reproducibility. Additionally, it will provide policy recommendations, and potential binding-pathway mechanisms to guide RIs toward sustainable operations, along with training programs and a certification framework to equip RIs with the skills for energy-efficient digital services management. Through this approach, GreenDIGIT will not only improve the environmental footprint of participating RIs but also establish scalable best practices for digital RIs across Europe.