As global concerns over climate change and environmental sustainability intensify, the IT industry faces increasing pressure to reduce its carbon footprint and optimize energy consumption. This research paper proposes a comprehensive framework for architecting sustainable IT infrastructures that prioritize green application deployment and energy efficiency. The framework integrates cloud-native architectures, energy-aware computing, and intelligent resource orchestration to minimize environmental impact while maintaining performance standards. Key strategies include the use of serverless computing, containerization, virtualization, and AI-driven energy optimization techniques. The proposed model also emphasizes sustainable lifecycle management, energy-efficient data centers, and smart load balancing to achieve long-term energy reductions. Through quantitative analysis and case studies, this paper demonstrates how sustainable IT architectures can significantly cut energy costs, enhance operational efficiency, and support global sustainability goals.