American Fiction (2023) presents Thelonious "Monk" Ellison's conflict as a Black writer confronting institutional expectations regarding what constitutes recognizable and authentic Black authorship. Although previous research has addressed stereotypes, parody, resistance, commodification, and issues of racial authenticity in both American Fiction and Erasure, the socio-categorical mechanisms that enable stereotypical representations to gain institutional credibility remain relatively underexplored. This study aims to analyze Monk's social categorization, his response to the prototype of Black authorship, and the consequences of Stagg R. Leigh's performance on his negotiation of social identity and individualized self-definition through the Tajfel-Turner Social Identity Approach. The study employed a qualitative descriptive design with theory-informed character analysis. From the entire film screening, 18 candidate scenes were identified and reduced to 14 primary analytical scenes. Data were analyzed through two-level coding, separating descriptive coding from theory-informed coding. The results of the study reveal five main patterns: Monk's categorization prior to Stagg's emergence, prototype resistance through satirical construction, strategic prototype performance, intragroup categorical evaluation through interactions with Sintara, and institutional validation and recirculation of Stagg's persona. The main finding indicates that the perceived fit between Stagg's performance and the prototype of Black authorship increases categorical recognizability, which can then be interpreted as authenticity. This study proposes prototype-based social recognition as an analytical synthesis to explain the relationship between perceived prototypicality and perceived authenticity, while also emphasizing that deliberate prototype performance is not identical to self-stereotyping or psychological internalization. The findings also indicate that resistance to externally imposed categorization does not automatically exempt Monk from categorical judgments about other members of the same broad social category.