This paper examined empirically the value of a conceptual model in which emotional stability and agreeableness contribute to engagement in aggression and violence (EAV) indirectly through irritability, hostile rumination and moral disengagement. Three hundred and forty young adults (130 male and 190 female) participated in the study. The average age of participants was 21 at time 1 and 25 at time 2. Findings attested to the role of basic traits (i.e. agreeableness and emotional stability) and specific personality dispositions (i.e. irritability and hostile rumination) in predisposing to EAV and to the pivotal role of moral disengagement in giving access to aggressive and violent conduct. In particular, the mediational model attested to the pivotal role of emotional stability and agreeableness in contributing directly to both hostile rumination and irritability and indirectly to moral disengagement, and to EAV. Agreeableness and hostile rumination contribute to moral disengagement that plays a key role in mediating the relations of all examined variables with EAV. Copyright © 2012 John Wiley & Sons, Ltd.