Researchers have demonstrated the importance of professional development experiences for in-service music educators that are content-specific and that cultivate meaningful partnerships with higher education faculty and preservice music teachers. The purpose of this mixed-methods study was to explore cooperating teachers’ perceptions related to hosting and mentoring student teachers. We interviewed 13 cooperating teachers to document their views. Based on interview results, we created and distributed an online questionnaire, with 102 cooperating teachers from five U.S. regions responding. Cooperating teachers’ motives for hosting student teachers were largely altruistic, and they identified various student teacher skills and university supervisor supports as being important. We suggest that the immersive experience of serving as a cooperating teacher may be a form of professional development.