Charlotte Moorman (1933–1991) was a Juilliard-trained cellist whose life and work made an indelible mark on the development of the American avant-garde. In her career, Moorman acted as a performer, collaborator, composer, administrator and muse. She solely founded the inaugural New York Avant Garde Festival, and subsequently directed fifteen of these festivals between 1963 and 1980, the feat for which she is most widely acknowledged today. Yet, her revolutionary performance practice, which blurred the lines between her life, her body, and her work, and brought into focus the dynamics of corporeality, the feminine body, female nudity and sexuality, and gendered politics within the contexts of musical performance, has so far escaped serious consideration in the written histories of the American avant-garde. This dissertation describes the nature of Moorman's practice as one that evolved to become inherently and irrevocably embodied, explores how this approach fell at odds with the pervasive avant-garde philosophies of music, and illustrates how her work troubles even a feminist musicological analysis. Further, through a contemporary critique of Moorman's oeuvre which centralizes the social, cultural, and political implications of her body in performance as integral to the work, this project offers a retrospective visibility to the artist which allows for a reframing of her practice as foundational to the aesthetic development of the postwar musical avant-garde. By way of these efforts, Moorman's legacy is presented as one that is both historically significant and vital to current and future musicological discourse.