We sought to determine who is involved in the care of a trauma patient. We recorded hospital personnel involved in 24 adult Priority 1 trauma patient admissions for 12 h or until patient demise. Hospital personnel were delineated by professional background and role. We cataloged 19 males and 5 females with a median age of 50-y-old (interquartile range [IQR], 35.5-67.5). The average number of hospital personnel involved was 79.71 (standard deviation, 17.62; standard error 3.6). A median of 51.2% (IQR, 43.4%-59.8%) of personnel were first involved within hour 1. More personnel were involved in direct versus indirect care (median 54.5 [IQR, 47.5-67.0] vs 25.0 [IQR, 22.0-30.5]; P < 0.0001). Median number of health-care professionals and auxiliary staff were 74.5 (IQR, 63.5-90.5) and 6.0 (IQR, 5.0-7.0), respectively. More personnel were first involved in hospital locations external to the emergency department (median, 53.0 [IQR, 41.5-63.0] vs 27.5 [IQR, 24.0-30.0]; P < 0.0001). No differences existed in total personnel by Injury Severity Score (P = 0.1266), day (P = 0.7270), or time of admission (P = 0.2098). A large number of hospital personnel with varying job responsibilities respond to severe trauma. These data may guide hospital staffing and disaster preparedness policies.