For decades, research has shown that personality can be a significant predictor of positive workplace outcomes, but with one caveat; it depends on the type of job. The current study uses structural equation modeling to test whether the theory of Purposeful Work Behavior explains how personality leads to Work Engagement. It was found that, as a group, three job characteristics (Task Identity, Feedback from Work, and Feedback from Others) and Achievement Striving mediate the relationship between Conscientiousness and experienced Meaningfulness, which subsequently predicts Work Engagement. Neuroticism was found to predict Achievement Striving, experienced Meaningfulness, and Work Engagement, but none of the job characteristics. The hypothesis that the three job characteristics would moderate the relationship between Achievement Striving and experienced Meaningfulness was not supported. Overall, the theory of Purposeful Work Behavior was mostly supported with regards to Conscientiousness but not for Neuroticism. Furthermore, the theory helps to explain how the two personality factors Conscientiousness and Neuroticism may influence the level of Work Engagement one experiences at work.