This study examines how the global diffusion of Hallyu (the Korean Wave) generates strategic synergies for Korean retail firms in their international expansion. While prior research has largely viewed Hallyu as a cultural phenomenon, this paper conceptualizes it as a reputational resource that lowers entry barriers, facilitates trust, and enables the co-creation of cultural and economic value in foreign markets. Drawing on the theoretical mechanisms of reputation renting, cultural hybridity, and bidirectional trust transfer, this study develops a stage-based model of global retail expansion. Through a comparative case analysis of global retailers (Walmart, Carrefour, Costco) and Korean convenience store chains (GS25, CU), the study finds that successful expansion follows a three-stage process: (1) In the entry stage, firms overcome the liability of outsidership by renting Hallyu’s reputational capital as a catalyst; (2) In the growth stage, they secure market settlement through co-creative hybridity, combining headquarters systemic capabilities with local partners contextual knowledge; and (3) In the maturity stage, a virtuous cycle of bidirectional trust transfer emerges, where corporate success reinforces the national brand, creating mutual reinforcement effects. These findings extend the revised Uppsala Model and trust transfer theory by elucidating the dynamic interplay between cultural soft power and retail hard power, offering practical implications for sustainable global strategy and ESG management.