The overall aims of this study were to identify qualities of interpersonal interaction within teacher-parent-pupil learning partnerships and to explore whether these characteristics were predictors of learning and teaching outcomes for teachers, parents and pupils participating in pursuit of expertise on musical instruments. This article presents the findings relating to how teachers' beliefs relating to interpersonal interaction with pupils and parents impacted on their professional satisfaction, self-efficacy, and involvement with pupils and parents. Two hundred and sixty-three violin teachers were surveyed, each completing a questionnaire that included measures of the interpersonal constructs of control and responsiveness as well as measures for outcomes that included professional satisfaction, teacher self-efficacy, and involvement with pupils and parents. The scales for control and responsiveness were subjected to a principal component analysis, revealing several underlying dimensions of these constructs. Multiple regressions revealed that facets of control bore significant correlations with all of the specified teacher outcomes, while the interpersonal factor that had the greatest influence overall was teacher sensitivity (a responsiveness component). At the heart of this finding is a model of a "responsive leader", providing authoritative direction but also compelled to respond to the individual pupil needs and parental wishes or circumstances. (Contains 11 tables.)