DescriptionPersonality psychology seeks to characterize, understand, and predict behavior. However, studies that utilize direct behavioral observation are few in number. The current study analyzes data from the Hawaii Personality and Health Cohort and links self-rated Big Five personality with directly observed behavior in a videotaped cognitive test conducted years later. The study also looks at the link between personality and performance, and how that relationship is mediated by behaviors. Correlations were conducted to assess the relationship between the Big Five Inventory and behaviors enumerated in the Riverside Behavioral Q-Sort. A significant number of correlations were found for Extraversion, Conscientiousness, and Openness. Regression analyses were conducted to determine associations among the Big Five traits, behaviors, and performance on the three sections of the Woodcock-Johnson III Tests of Cognitive Abilities: Brief Intellectual Ability. Meaningful relationships were found between Conscientiousness and all three sections of the BIA, and between Openness and two sections of the BIA. Bootstrapping was then employed to examine the mediating relationship of behavior for the personality-performance link. Some behaviors that showed mediation were “Speaks fluently; expresses ideas well,” “Shows interest in intellectual and cognitive matters,” and “Exhibits a high degree of intelligence.” This study begins to address the need to identify the mechanisms by which personality affects real-world outcomes.