Older youth served in the foster care system have elevated rates of mental health disorders and are high users of mental health services, yet concerns have been raised about the quality of this care. This paper describes the details of a psychiatric nurse’s work within a multidisciplinary team to address gaps in care for older youth with psychiatric disorders. We describe the process, outcomes, and lessons learned in developing and piloting a psychiatric nurse intervention for older youth in the foster care system as part of a multidimensional treatment foster care program. Our experiences support further work to develop a role for nursing to improve the quality of mental health treatment in foster care.