Software-Defined Networking (SDN) enhances network management through centralized, programmable controllers. However, frequent changes in network topology due to high traffic increase control message overhead, leading to congestion in some controllers while others remain underutilized. Effective switch migration is essential for restoring load balance among controllers. Existing methods often result in post-migration congestion and potential controller failure, as they do not adequately consider the combined impact of switch connectivity and workload on controllers during immigrant switch selection, nor do they employ a dual Multicriteria Decision Method (MCDM) for selecting destination controllers. This study proposes ATH-TOPSIS Based Reliable Switch Migration (ATRSMA) to address these limitations. ATRSMA enhances migration reliability by selecting immigrant switches based on their workload and network connectivity. Moreover, it uses a hybrid MCDM approach—combining the Analytic Hierarchy Process (AHP) and Technique for Order of Preference by Similarity to the Ideal Solution (TOPSIS)—for destination controller selection. AHP is used to weigh the preference of factors such as current load and available CPU, memory, bandwidth, and port resources, while TOPSIS ranks the controllers to determine the optimal controller. Experimental results show that ATRSMA reduces controller response time by 22%, improves reliability by 77%, and achieves a 37% congestion restoration rate compared to existing solutions. These results establish ATRSMA’s success and novelty in enhancing SDN load imbalance and reliability.