A system is a collection of entities (ie, widgets, molecules, people, businesses) that interact in such a way that their resulting collective behavior is not immediately apparent by viewing the collected items separately. Hospital-based health care meets the definition of a system, but further specification is helpful to describe the value of components in the system. Complexity science offers a chance to reconceptualize our understanding of health care to an environment of connected parts operating together and adapting on the basis of inputs and outputs. The purpose of this conceptual article is to apply complexity science principles to acute care physical therapy in order to provide perspective on the value of the physical therapist in the hospital environment and on the contextual factors that influence the profession's value. We present a model, the Socio-Ecological Model for Acute Care, and apply this model to physical therapy in order to describe the interrelated factors influencing the profession's value to individual patients, to the hospital units on which they practice, to the hospital system as a whole, and how they contribute to policy discussions. Yet, this value is difficult to distinguish due to the multifarious inputs into the system. Providing a clear description of the value of physical therapy in hospital settings is essential in our current health care environment that is increasingly cost-conscious. We provide perspective for clinicians and health care leaders while suggesting needs for future research.