Seriosa music in Indonesia is often viewed with ambivalence; it is perceived as a product of Western elitist culture, yet it served as a powerful medium for articulating nationalist spirit during the independence revolution. This article explores the position of Seriosa within the discourse of national identity, focusing on the figure of Cornel Simanjuntak. Utilizing a post-colonial perspective, specifically Homi K. Bhabha’s concepts of mimicry and hybridity, alongside a comparative analysis of the film Oeroeg (1993), this study examines how the colonized subject adopts the colonizer's culture as a strategy of resistance. The analysis reveals that Cornel Simanjuntak did not merely imitate Western musical aesthetics (diatonic scales); rather, he engaged in cultural hybridity, transforming this imitation into a form of mockery or resistance against colonial dominance. Cornel’s decision to move beyond the traditional pentatonic scale and embrace modern music manifests a fluid and progressive national identity, rejecting a static or romanticized view of the past. This study concludes that Seriosa represents a form of cultural negotiation (hybridity) that produces a liberated subject capable of transcending the East-West dichotomy.