Findings from a year-long exploratory study aimed at describing universal functions of medical social work with interdisciplinary teams in acute care settings are reported here. A universal taxonomy of interdisciplinary social work skills and competencies was empirically identified through a participatory action research framework. Findings support previous conceptual descriptions of medical social work's overarching and historical role to help interdisciplinary teams in acute care to consider patients' home environment, knowledge, beliefs, culture, and resources during assessment, treatment, and discharge planning. The empirically determined taxonomy reported is intended to provide social workers a framework with which to articulate and evaluate their core competencies on interdisciplinary medical teams.