This study investigates how plus-size consumers define and evaluate perceived fit and fashionability in their purchase decisions regarding denim jeans. Despite the fashion industry’s increasing efforts toward size inclusivity, a significant gap persists between market offerings and consumer experiences, leaving plus-size individuals frequently dissatisfied. To address this gap, this research utilizes the Functional, Expressive, and Aesthetic (FEA) framework to capture the complex, subjective, and lived experiences of these consumers. Using a qualitative approach, semi-structured wardrobe interviews were conducted with ten US-based plus-size women via video conferencing. Participants engaged with their own denim collections—selecting their “best-fitting” and “most fashionable” pairs—to articulate the nuances of their evaluative processes. The findings reveal that fit is a multidimensional construct in which functional comfort is inextricably linked with expressive body presentation and internal confidence. Fashionability is conceptualized as a dual-layered construct shaped by the intersection of collective trend alignment and individual identity, a relationship heavily mediated by “aesthetic fit”—defined as the visual harmony between the garment and the wearer’s specific body. Specifically within the context of denim, consumers navigate unique structural constraints, such as waist-to-lower body mismatches, and utilize specific silhouettes as strategic tools for body-image management. Furthermore, while fit remains the dominant prerequisite in purchase decisions, final outcomes are often dictated by forced compromises resulting from the limited availability of extended sizing. This study contributes to a deeper understanding of plus-size consumer behavior by demonstrating that true inclusion requires more than technical size expansion. It emphasizes the need for an integrated design approach that prioritizes anatomical diversity, functional ease, and style relevance to better empower underserved consumers within the fashion system.