This article investigates how the Republic of Korea has strategically employed its cultural production globally known as Hallyu (the Korean Wave) as a cornerstone of its soft power strategy in the 21st century. Based on a systematic literature review and analysis of official policy documents, this study explores how South Korean cultural exports, particularly K-pop, television dramas, and digital content, have evolved into tools of symbolic and economic diplomacy. The methodology includes a structured review protocol detailing the databases searched, keywords, and inclusion/exclusion criteria. Findings indicate that Hallyu functions not only as a cultural trend but also as a coherent state-led diplomatic project with tangible political and commercial outcomes. In particular, the study highlights the role of popular music groups such as BTS and BLACKPINK in fostering bilateral cooperation, promoting Korean identity abroad, and shaping international discourse on innovation, diversity, and modernity. It also critically examines regional resistance and structural vulnerabilities in the strategy, such as over-reliance on digital platforms and cultural frictions in conservative regions. The study concludes that Hallyu represents a paradigmatic model of soft power that blends cultural attractiveness, institutional support, and global market dynamics.