The fostering of interdisciplinarity is increasingly requested of research organizations. However, conventional approaches to academic research management limit our understanding of the way interdisciplinary research (IDR) centers integrate multiple disciplines. This paper proposes a multilevel approach to explore the patterns of knowledge integration and the forms of research organization emerging from the practices and activities of IDR centers. Several bibliometric-based, network-oriented and visualization-rich approaches are used. The cases of two prominent IDR centers are considered: Harvard University's Wyss Institute and Kyoto University's WPI-iCeMS. At the macro level, our results show similarities in the scientific positioning of both IDR centers, which translate into differences in the nature, intensity and drivers of their knowledge interconnections at the meso-level. At the micro-level, we demonstrate that far from idealizations of full convergence, the realities of IDR centers are characterized by heterogeneous patchworks of multi-trajectory research domains—some of these enabling, others generating interdisciplinary knowledge. Differences in knowledge integration occur between but also, and more importantly, within IDR centers. Thus, tailored strategies tuned to the particularities of organizations and topic-based forms of research organization appear to cope better with interdisciplinary knowledge. The understanding of these inter- and intra-organizational differences proves crucial for effectively fostering knowledge integration. An integrated model relating levels of research management and visualization approaches is proposed for the management and assessment of knowledge integration in IDR centers.