Personality traits and cognitive performance are related, but little work has examined how these associations vary by personality facet or age. 154 adults aged 22 to 84 completed the Brief Test of Adult Cognition by Telephone (BTACT) and the NEO Five Factor Personality Inventory. Hierarchical multiple regression analyses showed negative emotional aspects of personality (neuroticism, depression) were associated with lower reasoning, and social aspects of personality (assertiveness) were associated with faster reaction time, yet lower reasoning. The association between neuroticism and performance was found primarily among younger adults. In older adulthood, better performance was associated with positive emotional aspects of personality. We discuss how personality may have different associations with performance across age and the implications for possible interventions.