The interaction among a group of musicians before, during, and after the performance of a jazz standard is analyzed to show the interdependence of jazz aesthetics and jazz ethics. The authors argue that what makes jazz distinct from other kinds of musical traditions is not just the ubiquity of improvisation in the genre but the vulnerability that jazz improvisation always generates—a vulnerability that is due to the genre’s reliance on both shared conventions and partly unpredictable individual choices. Analyzing video recordings of a university course on jazz organized to reproduce the setting of a jam session, the authors examine in detail the interactional assumptions and consequences of choices made by band members during the performance of “Softly, as in a Morning Sunrise.” The authors’ analysis shows how musicians position themselves to be responsive to one another as the song progresses, starting from an improvised “introduction” that sets the tempo, rhythm, and style of the song and continuing with smooth transitions from one solo to the next. Drawing from Erving Goffman’s ideas about the presentation of self and the phenomenology of Emmanuel Levinas, the authors examine the ethical implications of a musical “vacuum” that was created by one musician’s decision to wait to take his solo. In the interaction, the other musicians responded to the vacuum by assuming responsibility for the group’s performance and, more broadly, the performance of the jazz tradition, and this chapter uses their actions to illustrate how “jazz etiquette” operates as a practice that includes aesthetic, ethical, and practical concerns.