Anger is a universal emotion, existing in both state and trait dimensions, that is experienced by most people several times per day to several times per week. Anger is thought to have evolved as a means to recalibrate situations to more align with an individual’s goals or motivations. However, inappropriate or excessive anger is related to a host of severe intrapersonal and interpersonal consequences. The current thesis addresses gaps in the empirical literature and investigates how anger and the closely related constructs of hostility and aggression associate with individual differences across multiple domains. Firstly, using data from a nationally-representative US sample, the current thesis presents evidence of both direct effects of and interactions amongst core personality traits on the pathway towards trait anger and anger expression styles. Specifically, results reveal that conscientiousness moderates neuroticism’s effect on an individual’s ability to control their anger, and, in a three-way interaction, conscientiousness and agreeableness moderate neuroticism’s effect on an individual’s level of trait anger, the likelihood that anger is expressed outwardly, and the likelihood of aggression. Secondly, the current thesis presents evidence of associations between core personality traits and judgments of hostile intent, and the mediating effect of higher-order personality characteristics. Notably, results indicate that an inflated sense of self-entitlement and the social projection of one’s own traits onto others mediated honesty-humility’s relationship with a factor underlying judgments of hostile intent. Thirdly, using voxel-based morphometry the thesis presents evidence, albeit at the uncorrected level, of correlations between cortical regions’ gray matter and trait anger and anger expression style. Finally, the thesis concludes by embedding these results in the context of prior research investigating the experience of anger and contemporary models of anger and its expression.