The main aim of this study was to (a) test the construct validity of complex problem solving (CPS); (b) examine the ability to acquire knowledge as a mediator of the relationship between intelligence and CPS performance; and (c) investigate the personal need for structure as a moderator of the relationship between intelligence and knowledge acquisition. A total of 128 participants completed the self-report Personal Need for Structure scale; the Vienna Matrix Test to assess intelligence; and a new multiple complex systems approach method to assess CPS skills. When analyzing the internal structure of CPS, we found that a two-dimensional model consisting of knowledge acquisition and knowledge application best fitted the data. We also found that the relationship between intelligence and CPS performance was partially mediated by the ability to acquire knowledge. Finally, personal need for structure did not moderate the relationship between intelligence and the ability to acquire knowledge. Our results indicate a need to further investigate other cognitive abilities in interaction with contextual situational factors that could additionally explain variance in CPS performance. Moreover, we also highlight the importance of deeper observation of the knowledge application phase of CPS process.