One of the most recognized icons of Mexico is the mariachi moderno tradition, which in the global popular imaginary, is associated with nostalgic, humorous, and emotional songs of love, heartache, death, drinking, and place. Inseparably fused to tequila and the historic charro figure, mariachi moderno completes a symbolic trinity of hetero-nationalist culture, conveyed within a popular imaginary of authentic mexicanidad (Mexican-ness). For mariachis and aficionados in Mexico, performative hypermasculine machismo acts as a perceptual baseline, structuring modes of feeling that signify an experience of authentic nationalist musicality This process is musically constructed in an incorporation of bodily movement, instruments, sound timbres, and symbolic clothing, simultaneously gestured with a heavy male-accent fusing an experience that feels genuinely Mexican. This reflexive signification is a consequence of the lived experience, shared dispositions, and competencies learned in the habitus, constituting real and imagined notions of hetero-nationalist culture. I refer to this musical semiosis as mariachismo, a neologism describing an intersubjective experience of machismo-infused mariachi subjectivity, ritualized through repeated gestures of sound, lyric, and corporeality. The semiotic power of mariachismo is most potent for subjects enculturated to Mexico's hetero-nationalist culture, shaped by popular imaginaries operationalizing gender and mexicanidad, connecting the two, making them feel unquestioned, natural, and unmediated. The ontology of mariachismo, is in part revealed through an analysis of metaphors used by practitioners and aficionados to describe mariachi's musical techniques and social practices. These metaphors index an archive of embodied knowledge, a lived experience where hypermasculine subjectivity is reified and other forms of gendered performativity, including femininity and non-hetero subjectivities, are marginalized or purposefully subverted. Employing ethnomusicological analysis and building on concepts of habitus, performativity, and musical semiotics, this dissertation illustrates how mariachismo aesthetically enacts sonic-somatic gestures, enhanced by fetishized clothing, and construed within a symbolic music practice, all of which ritualize a perceptual experience of authentic mariachi musicality.