This paper argues that stylistic fusion in Béla Fleck’s banjo practice operates not primarily through genre hybridization or stylistic borrowing, but through the renegotiation of instrumental roles, technical practices, and performance authority across musical contexts. Through comparative analysis of two contrasting projects—Perpetual Motion (2001), which adapts Western art music repertoire for banjo-centered ensembles, and Thrown Down Your Heart (2009), a documentary project documenting Fleck’s collaborations with West African musicians—the paper examines how fusion is enacted through shifting configurations of leadership, learning, and ensemble interaction. In Perpetual Motion, Fleck’s arrangements of works by composers including Bach, Beethoven, Liszt, and Debussy involve the development of new banjo techniques and ensemble orchestrations that substitute bluegrass instruments for classical ones, resituating Western art music within an American vernacular performance framework while maintaining the banjo’s central musical authority. In contrast, Thrown Down Your Heart positions Fleck as a participant-observer within local musical systems, where authority and decision-making are frequently ceded to collaborating musicians, reshaping both musical outcomes and modes of transmission. By foregrounding sonic structure, instrumental technique, and interactional dynamics, this paper demonstrates how Fleck’s fusion practices reconstitute the banjo from a conventionally leading bluegrass instrument into a flexible, context-responsive musical agent. More broadly, the paper proposes an ethnomusicological approach to fusion that emphasizes performance roles and instrumental identity as socially negotiated processes rather than stable genre categories.