Boris Schwarz once characterized Brahms's Violin Concerto, op. 77, as an “intangible interplay between the art of Brahms and that of Joachim.” The celebrated violinist was not only the inspiration for this concerto; he also played a crucial role in its compositional genesis and early performance history. But while Joachim's compositional contributions to the concerto have been well documented, his importance as a performer is usually acknowledged only in vague terms. We sense that Joachim the performer is somehow “in” this concerto without being able to articulate how. This article examines the intersections between Joachim's style and persona as a performer, the cultural meanings ascribed to performance, and specific formal and expressive features of the Violin Concerto. Particularly important was Joachim's perceived ability to present composed musical works as though they were being improvised, created on the spot through a mysterious fusion of Joachim himself with the mind and spirit of the composer. In the later nineteenth century, as the practice of improvisation began to disappear from the concert stage, improvisation could represent a lost ideal of spontaneous, unmediated subjective expression. An analysis of the concerto's first movement shows that it thematizes tensions between two contrasting visions of creativity—one involving spontaneous inspiration and improvisation at an instrument, the other, the rigors of logical, planned out, and written composition. These expressive features take on additional meanings when considered in the context of Joachim's performances of the concerto, and they allow for a recovery of some of its historical meanings that resided not only in the notated score, but also in performed events.