Integrating Theory, Evidence and Action (ITEA) is a type of systematic review methodology, which was used to investigate the underlying agents of therapeutic change in one filial therapy approach, child-parent relationship therapy (CPRT). The therapeutic powers of play (TPoP) framework was applied to recent peer-reviewed journal articles to extract evidence that TPoP are activated in CPRT. Data were deconstructed to determine the prevalence of TPoP within each subsystem of therapy: the child, parent, therapist, their relationships, and family environment. Meta-analyses revealed that play therapy with full parental involvement (filial therapy) yielded greater effect size than partial or no parental involvement (Lin & Bratton, 2021). Greater understanding about the mechanism of therapeutic change in filial therapy may allow therapists to enhance the strengths of the intervention and understand modifications necessary to individualize treatments for specific presenting problems or populations. A diagram will be presented to conceptualize the sequences and subsystems in CPRT. This study highlights that filial therapy is a developmentally sensitive intervention which facilitates therapeutic change across the life span and throughout the family system. Filial therapy activates all TPoP except counterconditioning fears. The highest number of TPoP was evidenced within the parent-child relationship subsystem. Filial therapy facilitates change in social relationships in families through activating attachment, social competence, empathy, and therapeutic relationships. Explicit integration of TPoP through development of a TPoP goal-setting tool or providing specific feedback about observed activation of TPoP could potentially further strengthen the therapeutic effect of filial therapy. Further observational assessment is recommended to identify the prevalence of implicitly activated TPoP.