We examined relations between the Five-factor model (FFM) domains and facets of Agreeableness and Conscientiousness, hypothesized behavioral manifestations of these traits (e.g., social information processing and delay discounting), and externalizing behaviors in an undergraduate sample. Agreeableness and Conscientiousness were differentially related to the externalizing behaviors and the laboratory tasks, which in turn evinced significant relations with externalizing behaviors. The personality facets displayed evidence of modest incremental validity over the broader domains and were related to the externalizing behaviors even when controlling for the social information processing and behavioral discounting variables. In general, the results support the validity of the FFM domains and facets, particularly Agreeableness, in the prediction of a variety of externalizing behaviors.