The present research tested the relations between a battery of background factors and counterproductive work behaviors in a 23-year longitudinal study of young adults (N = 930). Background information, such as diagnosed adolescent conduct disorder, criminal conviction records, intelligence, and personality traits, was assessed before participants entered the labor force. These background factors were combined with work conditions at age 26 to predict counterproductive work behaviors at age 26. The results showed that people diagnosed with childhood conduct disorder were more prone to commit counterproductive work behaviors in young adulthood and that these associations were partially mediated by personality traits measured at age 18. Contrary to expectations, criminal convictions that occurred prior to entering the workforce were unrelated to counterproductive work behaviors. Job conditions and personality traits had independent effects on counterproductive work behaviors, above and beyond background factors.