The rapid digitization of global economies has generated an unintended environmental consequence: the Information and Communication Technology (ICT) sector now contributes an estimated 1.5% to 4% of global greenhouse gas emissions, a figure comparable to the aviation industry. This paper presents a comprehensive framework for Green ICT that addresses environmental sustainability across the entire digital ecosystem. Drawing on foundational models and contemporary case studies, the proposed framework integrates four vertical pillars—Lifecycle Management, End-User IT, Enterprise and Data Centre Infrastructure, and IT as a Low-Carbon Enabler—with five horizontal action dimensions: Attitude, Policies, Practices, Technologies, and Metrics. The framework incorporates recent advances in renewable energy procurement, AI-driven optimization, circular economy principles, and standardization efforts