This work aims to develop and investigate a mathematical model and method for designing a cyber-resilient and sustainable network. The proposed approach focuses on optimizing the use of available network equipment by considering cost, configuration, performance (throughput), security level, and the network’s ability to maintain stable operation in a dynamic environment. The developed solution offers an integrated, optimized framework for selecting network topology, equipment characteristics, communication links, and traffic distribution (routing). The design method is based on solving a Mixed-Integer Linear Programming (MILP) optimization problem and assumes that the potential locations for network routers are known in advance. A unified mathematical formulation enables a coordinated approach to selecting the network topology, determining the connection order between access networks and core routers, and specifying equipment characteristics. Cyber resilience is incorporated into the designed solutions by including security indicators directly in the objective function, namely, compromise probabilities, Common Vulnerability Scoring System values, and information security risks associated with network equipment. This approach enables synthesizing networks with specified or forecasted cyber resilience characteristics. A cyber-resilient and sustainable network was designed to validate the proposed method based on initial data, including different types of routers, interface modules, and network load volumes. The calculation results confirmed the adequacy of the mathematical model. As network performance requirements increased, the method dynamically involved additional network resources in the design solution. This process was accompanied by expanding the network topology and deploying higher-performing and more expensive routers and interface modules.