The purpose of this thesis is to assess theories of emotion, meaning, and expression in music from the perspective of the performer. While a significant body of research is devoted to theories about such matters—to which I will refer collectively as “theories of communicative content”—there is a general lack of attention paid to how such theories apply in actual music performance. In other words, these theories tend to avoid explicating not only how music conveys such content in acts of performance, but also how performers, through such acts, imbue music with communicative content. I seek to address this oversight because the process of applying communicative content in performance, indeed, the very process of performing itself, may offer insight into the mechanisms involved for making music meaningful and expressive. To that end, I will investigate evidence from actual musical practice and from actual music practitioners. The thesis will consider current research on expression, meaning, and emotion in music, propose a new model that derives from performance itself, and assess old and new models alike through case-study interviews with professional-level performers. By bringing the performer’s voice into the discussion, this thesis aims to formulate a model that not only gives an accurate account of how music becomes meaningful in performance, but also provides musicians with clearly defined methods for how to make music in ways that are emotionally charged and meaningfully expressive.