The increasing environmental impact of software systems calls for a structured integration of sustainability principles across the software development life cycle. This paper introduces a guideline-oriented framework that aligns software engineering practices with a green life-cycle perspective. Anchored in the DevOps methodology, which emphasizes rapid delivery and operational agility, our approach embeds environmental sustainability at each phase of the software life cycle–from planning and design to deployment and monitoring. Drawing on the Life Cycle Assessment (LCA) philosophy, we present actionable guidelines that enable teams to measure, manage, and improve the carbon and energy footprints of their software products. The proposed framework supports practitioners in reducing emissions, improving resource efficiency, and contributing to global climate goals, all without compromising development quality or velocity. This study provides a practical foundation for implementing sustainability as a continuous concern throughout software engineering processes.