Knowledge-intensive industries has become a major source of competitive advantage and innovation. However, there is no general agreement about the innovation pathways of knowledge-intensive enterprises. A possible explanation for this might be that the complex pathways has thus far been studied using regression models that capture only the main regression effects. To address this issue, we use fuzzy set qualitative comparative analysis that examines relationships (even asymmetrical) between the enterprises’ innovation activity and all possible configurations of its determinants, including obstacles, knowledge sources, collaborative activities and R&D. We investigate this framework in the case study of German knowledge-intensive enterprises. The results show that several pathways act as sufficient conditions for product innovation. However, the effects of these conditions are asymmetric. In addition, the following complementary relationships between the determinants were observed: (1) public support and education knowledge source; (2) internal and external R&D and collaboration on innovation; and (3) internal and market knowledge source and publicly available knowledge acquired from other sources such as conferences, journals and professional associations. Thus, these findings may provide an explanation of the inconsistent effects observed in previous studies on product innovation.