In this article, we discuss the role of the therapist in change in couple and family therapy. We argue that the therapist is a key change ingredient in most successful therapy. We situate our discussion in the common factors debate and show how both broad and narrow common factor views involve the therapist as a central force. We review the research findings on the role of the therapist, highlight the strengths and weaknesses of this literature, and provide directions for future research. We then use this review as a foundation for our recommendations for theory integration, training, and practice.