The health care delivery system in the United States, structured to provide single-disease care, presents unique challenges for patients with complex physical and psychiatric comorbidities. Patients in these populations are often referred to multiple specialty clinics, encounter little continuity of care or collaboration among their providers, incur high health care costs, and experience poor treatment outcomes. Given these barriers, questions remain about the extent to which siloed and fragmented care, as opposed to the complex nature of the illnesses themselves, contribute to poor outcomes. If given the opportunity to receive well-integrated, consistent, and personalized care, can patients with historically difficult-to-treat comorbid medical and mental illnesses make progress? This article describes an innovative model of care called functional rehabilitation that is designed to address existing barriers in treatment. The functional rehabilitation program seeks to disrupt the escalating effects of interacting comorbidities by offering highly collaborative treatment from a small team of clinicians, personalized interventions using a shared decision-making framework, multipronged treatment options, colocation in a large hospital system, and significant 1:1 time with patients. The article includes a case example with longitudinal outcome data that illustrates how progress can be made with appropriate programmatic supports. Future research should examine the cost-effectiveness of this model of care.