Purpose: The aim of this study was to assess the effect of an intensive cognitive and communication rehabilitation (ICCR) program on language and other cognitive performance in young adults with acquired brain injury (ABI). Method: Thirty young adults with chronic ABI participated in this study. Treatment participants (n = 22) attended ICCR 6 hours/day, 4 days/week for at least one 12-week semester. Deferred treatment/usual care control participants (n = 14) were evaluated before and after at least one 12-week semester. Pre- and post-semester standardized cognitive assessment items were assigned to subdomains. Between-groups and within-group generalized linear mixed-effects models assessed the effect of time point on overall item accuracy and differences by item subdomain. Subdomain analyses were adjusted for multiple comparisons. Results: Between-groups analyses revealed that treatment participants improved significantly faster over time than deferred treatment/usual care participants in overall item accuracy and specifically on items in the verbal expression subdomain. Investigating the three-way interaction between time point, group, and etiology revealed that the overall effects of the treatment were similar for individuals with nontraumatic and traumatic brain injuries. The treatment group showed an overall effect of treatment and significant gains over time in the verbal expression, written expression, memory, and problem solving subdomains. The control group did not significantly improve over time on overall item accuracy and showed significant subdomain-level gains in auditory comprehension, which did not survive correction. Conclusions: Sustaining an ABI in young adulthood can significantly disrupt key developmental milestones, such as attending college and launching a career. This study provides strong evidence that integrating impairment-based retraining of language and other cognitive skills with "real-world" application in academically focused activities promotes gains in underlying cognitive processes that are important for academic success as measured by standardized assessment items. These findings may prompt a revision to the current continuum of rehabilitative care for young adults with ABI.