Cloud and network infrastructure automation has emerged as a foundational pillar in the design, deployment, and management of modern enterprise applications. As organizations transition toward hybrid, multi-cloud, and cloud-native architectures, traditional infrastructure management approaches—characterized by manual provisioning, hardware-dependent configurations, and siloed operational workflows—have proven increasingly inadequate. Manual configuration processes are not only time-consuming and resource-intensive but also susceptible to human error, configuration drift, security vulnerabilities, and scalability limitations. In contrast, automation introduces programmable, policy-driven, and repeatable mechanisms that enhance operational efficiency and infrastructure reliability. Automation technologies such as Infrastructure as Code (IaC), configuration management frameworks, containerization and orchestration platforms, and software-defined networking (SDN) have redefined how enterprises manage compute, storage, and networking resources. IaC enables declarative infrastructure provisioning through version-controlled templates, ensuring consistency and reproducibility across environments. Configuration management tools enforce system states and security policies at scale, while container orchestration platforms provide dynamic workload scheduling, auto-scaling, and self-healing capabilities. SDN introduces centralized, programmable network control, improving agility and security in distributed environments. Together, these technologies create cohesive, self-scaling, and resilient infrastructure ecosystems that support rapid application deployment and continuous integration/continuous delivery (CI/CD) practices. This review systematically examines the evolution of cloud and network automation, analyzes core enabling technologies, and presents architectural frameworks that integrate automation across enterprise IT layers. Furthermore, it evaluates the strategic benefits of automation—including enhanced scalability, cost optimization, improved compliance, operational resilience, and reduced downtime—while addressing implementation challenges such as governance complexity, multi-cloud integration, skill gaps, and security risks. Emerging trends such as Artificial Intelligence for IT Operations (AIOps), intent-based networking, Zero Trust security automation, and edge infrastructure orchestration are also discussed to highlight the trajectory toward intelligent and autonomous infrastructure management. Overall, infrastructure automation is not merely an operational enhancement but a strategic enabler of digital transformation. As enterprise systems grow in scale and complexity, automation-driven frameworks will increasingly define competitive differentiation, innovation velocity, and long-term sustainability in digitally transformed organizations.