The purpose of this study was to analyze the effect of the introduction of an all-in workflow concept that included direct computed tomography (CT) scanning in the trauma room on mortality and functional outcome of trauma patients with severe traumatic brain injury (TBI) admitted to a level-1 trauma center. To this end, a retrospective comparison was made of a 1-year cohort prior to the implementation of the all-in workflow concept (Pre-CT in trauma room cohort [Pre-TRCT]) and a 1-year cohort after the implementation (Post-TRCT). All severely injured TBI patients aged 16 years or older that were presented in our level-1 trauma center and that underwent a CT of the head were initially included. Severe TBI was defined as an Abbreviated Injury Scale (AIS) score of >2 of the head region following trauma. Primary outcome parameter was TBI-related mortality during primary hospital admission. Secondary outcome parameter was the functional outcome based on GOS-Extended. A total of 59 patients were included in the Pre-TRCT and 49 in the Post-TRCT. Median age was 49 years in the Post-TRCT and 44 years in the Pre-TRCT (not significant [NS]). Median ISS was similar (ISS = 25). Median Head-AIS was higher in the Post-TRCT (5 vs. 4, NS). Initial CT scanning was completed faster in the Post-TRCT. There was a significant difference of 23% mortality in favor of the Post-TRCT for TBI-related mortality during primary hospital admission (p < 0.05). For acute neurosurgical interventions, time until intervention tended to be faster in the Post-TRCT (NS). Functional outcomes for survivors were higher in the Post-TRCT (6 vs. 5, NS).