This Special Issue of Clinical Psychology: Science and Practice provides a series of articles detailing efforts to consider the concepts of emotion and emotion regulation in relation to clinical assessment and psychopathology intervention efforts across the lifespan. In our commentary, we review some common themes and challenges presented in these articles to move forward the discussion of emotion's role in psychological therapy. We discuss efforts to conceptualize the role of context in defining emotion concepts and maximizing the relevancy of such concepts to treatment. We review the importance of imbuing efforts to develop emotion-focused treatments with emphases on positive, as well as negative, emotions and flexibility in the expression of these emotions. We also highlight the relevance of a lifespan developmental approach to the accurate use of emotion and emotion regulation concepts within treatment. Finally, we discuss the application of these issues to our own treatment development and evaluation efforts regarding a unified approach to the treatment of emotional disorders in adults and adolescents.