Aim To examine whether a hospitalist‐directed interdisciplinary (ITD) team in an internal medicine residency program enhances the hospital and clinical outcomes for seniors with acute medical illness. Methods Seniors admitted to a USA teaching hospital medical floor‐teaching services were allocated to the ITD (n = 379) and usual care teams (n = 383). Compared with the usual care team, the ITD team physicians carried out daily “geriatric” assessment and management, and led ITD team meetings. Results The mean probability of functional decline on hospital discharge in the ITD team (25%; 95% CI 19–30%) was significantly lower than that in the usual care team (36%; 95% CI 30–43%; OR 0.35; 95% CI 0.10–0.92; P < 0.001). The mean probability of delirium in the ITD team (26%; 95% CI 20–32%) was significantly lower than that in the usual care team (34%; 95% CI 28–41%; OR 0.48; 95% CI 0.16–0.97; P = 0.03). The mean probability of transition to an institution in the ITD team (18%; 95% CI 13–23%) was significantly lower than that in the usual care team (26%; 95% CI 19–32%; OR 0.41; 95% CI 0.14–0.95; P = 0.01). Conclusions Hospitalist‐directed ITD team care is associated with reductions of functional decline, delirium and transition to an institution for seniors with acute medical illness. Geriatr Gerontol Int 2013; ●●: ●●–●●.