This paper explores the replanning, reconstruction, and rebranding of Austro-Hungarian military buildings, encompassing common military administrative, healthcare, and housing facilities as well as railways that were under military jurisdiction, and their profound influence on the development of Banja Luka, Bosnia and Herzegovina. These structures, originally built for military and logistic purposes during the Austro-Hungarian period (1878–1918), played a pivotal role in shaping the city’s urban and architectural landscape. The study employs historical analysis of archival documents, maps, and photographs, combined with contemporary field observations that assess the current state and adaptive reuse of these buildings. This approach allows for a comprehensive understanding of the buildings’ transformation over time, from symbols of military authority to cultural and social landmarks within the city. The key periods of transformation—between 1945–1991 and post-1995—were largely driven by changes in national politics, military ownership, and local urban development policies that promoted the urbanization of unused military zones. The findings reveal a dynamic process of adaptive reuse, wherein the rebranding of these historical edifices has repurposed them into cultural, educational, and public spaces. These adaptive transformations not only preserved the architectural integrity of the buildings but also revitalized their roles in the community. The study concludes that Banja Luka’s experience serves as a model for sustainable heritage management, demonstrating the balance between historical preservation and modern urban development. The results highlight how the city successfully merged its rich architectural past with contemporary needs, contributing to its cultural identity and urban growth.