The study aimed to evaluate the possible mediating effect of two independent variables, self-efficacy and self-control, and to analyse the role of personality traits in the manifestation of criminogenic behavior. A total of 850 detainees from Romania, aged between 21 and 71 years (mean age = 38.7; standard deviation = 10.58), completed the CP5F Personality Questionnaire, the Criminogenic Cognitions Scale (SCC), the Machiavellianism Scale, and the Self-Efficacy Scale. The mediation model showed the following. Self-efficacy and self-control parallelly mediate the relationship between personality (p < 0.05) and the negative attitude toward the individual/authority (p < 0.01). As the score for self-efficacy increases, the score for Machiavellianism and the score for the negative attitude toward the individual also increase. As the score of self-control increases, the score for Machiavellianism decreases. The personality score explains approximately 27% of the variance in the self-efficacy score and 7.2% of the variance in the self-control score (p < 0.001). Self-control and self-efficacy are psychological dimensions that must be developed from adolescence, but in the direction of desirable, prosocial behaviours to prevent the formation of a criminal identity. Strengthening personality factors (Extraversion, Agreeableness, Conscientiousness, Emotional Stability, and Autonomy) can lead to a decrease in negative attitudes toward authority and the individual, which can result in a decrease in recidivism.