With the intent of informing the practice of music teachers navigating “multi-musicality” in their classrooms, this qualitative study, employing case study and narrative research tools, investigates the experiences of three musical “boundary crossers”—professional musicians whose work traverses the popular–classical divide. Three questions guided the inquiry: (a) How do professional musicians describe the experience of boundary crossing from one musical domain to another? (b) What musical skills do these professionals find valuable for their work in various domains, and what skills have they acquired or adapted in crossing musical boundaries? and (c) How does working in one musical domain influence work in another? Each participant navigates the balance between and the integration of their classical and popular musicianship(s) differently. All acknowledge that classical training, although it may afford some advantages, also can be a hindrance for individuals pursuing the creation and performance of music in a popular domain. Findings point to the need for functional piano skills, practical application of ear training, and development of a musical value set that includes “focused simplicity.” The findings have implications for how preservice teachers develop musical versatility, enabling them to respond to students’ varied interests and needs.