This study examines the domestic deployment of the Republic of Korea (ROK) Armed Forces, with a focus on its expanded role in disaster response and public support, particularly during the COVID-19 pandemic. While the ROK military has traditionally been tasked with national defence, its responsibilities have evolved to include non-military missions under the framework of comprehensive security. The paper analyzes the constitutional and legal basis for domestic military deployment, the institutional mechanisms governing its operations, and its historical precedents. It highlights how the COVID-19 crisis accelerated military involvement in public health responses, raising concerns about the infringement of conscripted citizens’ rights and the broader implications for civil-military relations. The findings reveal that, despite the military’s contributions to pandemic control, public perceptions of military service and institutional reliability remained largely unchanged. The study concludes with policy recommendations to balance military involvement in public crises while ensuring civilian oversight, legal accountability, and the protection of service members’ rights.