Strong therapeutic relationships built on trust are essential to effective mental and behavioral health services. Regularly eliciting feedback from clients can help develop these relationships, and using tools specifically designed to aid in eliciting client feedback are particularly beneficial to the client/provider therapeutic alliance. With the growing trend of technology-based health care delivery, adopting technology-based health care delivery modalities such as mobile applications (apps) have the potential to increase the accessibility and real-time capacity of client feedback tools. A randomized control trial was used to investigate the effectiveness of a client feedback mobile app in fostering therapeutic relationships of youth in care at a large, multi-state behavioral healthcare organization. Compared to the control group (n = 124), individuals in the intervention group (n = 119) experienced faster development of a strong working alliance with their service provider. These findings have relevant implications to the landscape of child welfare services, in which services are often abbreviated due to systems mandates or brief by design.