This study examines the genre characteristics of the SBS drama On Air (2008) from three dimensions―trendy drama, professional drama, and post-trendy drama―in order to explore a transitional phase in the history of Korean television drama. On Air faithfully inherits the conventions of trendy drama, such as urban settings, sophisticated lifestyles, immediate emotional expression, and the consumption of star images. At the same time, by foregrounding the reality of broadcasting production and the conflicts inherent in professional domains, it actively incorporates the narrative traits of professional drama. Moreover, through the restraint of emotions, the emphasis on institutional structures, and the introduction of meta-narratives, the drama anticipates the aesthetic tendencies of post-trendy drama, thereby suggesting new modes of emotion and narrative structures in subsequent Korean dramas. Accordingly, On Air can be defined as a hybrid and transitional text in which three genre codes intersect and converge, demonstrating that the evolution of Korean drama has not been linear but rather characterized by complex processes of genre hybridity. This study highlights On Air as a key indicator of a transitional moment in Korean drama history, and it contributes foundational insights for further inquiry into the future reconfiguration of genres and aesthetic transformations in Korean television dramas.