Purpose/Objectives: To determine key dimensions relevant to recovery in the postacute period for persons with traumatic brain injury (TBI) and to determine the ability of scores on these dimensions to predict participation outcomes for persons with TBI. Research Method/Design: This was a prospective cohort, observational study of 504 persons with medically documented TBI. Participants completed a comprehensive battery of measures including cognitive tests; questionnaires assessing self-report of physical, cognitive, and emotional symptoms and strengths; environmental supports; and a measure of participation outcome. Results: Participants were a predominantly male, ethnically/racially diverse sample of persons with complicated mild, moderate, and severe TBI. Variable cluster analysis identified 12 key dimensions of cognitive function, neurobehavioral complaints, personal strengths, physical symptoms and function, environmental supports, and performance validity. In unadjusted analyses, all 12 dimensions were predictive of participation outcome. In multivariable regression analysis with adjustment of all predictors for all other predictors, dimensions measuring memory, independence and self-esteem, resilience, emotional distress, physical functioning, and economic and family support made unique contributions to predicting participation outcome. Conclusions/ Implications: Findings add to our understanding of key aspects of functioning and self-perception for persons with TBI. Knowledge of the profile of an individual patient on these 12 dimensions may assist with development of a treatment approach for the person with TBI.