I describe the findings of one of the largest randomized controlled trials (RCTs) of rehabilitation after traumatic brain injury (TBI) ever conducted, examine the theoretical relationship between cognitive and functional rehabilitation after TBI, and describe the historical preference for cognitive (top-down) rather than functional (bottom-up) interventions. I also contrast the goals and principles of cognitive rehabilitation and of the neurofunctional approach of Giles and Clark-Wilson (1993; Giles, 2005)—a bottom-up approach. Findings of the RCT provide empirical support for both functional and cognitive interventions following acute TBI. In addition, they provide evidence that each type of intervention offers significant advantages for a specific subpopulation. The clinical implications of these findings for occupational therapy practitioners are discussed.