The present study investigates whether social support mediates the relationship between personality traits and physical functioning among African Americans over 2.5 years. Data were collected from a national probability sample of African American adults (analytic sample N = 312). Telephone surveys included measures of the five-factor model personality traits, social support, and physical functioning. Personality traits were assessed at Time 1 (T1), and social support and physical functioning were assessed 2.5 years later at Time 2 (T2). Physical functioning was assessed using the SF-12 at T2. Results indicated that T2 social support mediated the relationship between T1 personality traits and T2 physical functioning for the traits of conscientiousness, extraversion, agreeableness, and neuroticism, but not for openness to experience. This information may be useful to healthcare providers and community members in developing strategies targeting personality traits in cultivating social support for health promotion.