Recent research shows increasing efforts to unfold the potential of Cultural and Creative Industries (CCIs) for regions in order to pursue new sources of innovation, competitive edge and to manifest sustainable and inclusive growth paths driven by creativity. Due to its strong commitments to the Sustainable Development Goals (SDGs) of the United Nations, on the global level, the Baltic Sea Region (BSR) has become a role model in sustainable development. Yet, individual BSR countries face challenges in the implementation of those goals. In this light, by building on the intermediate results (2017–2020) of two EU Interreg projects—Creative Ports and CTCC—this research reveals CCIs’ potential for sustainable development avenues. The investigation is based on case study methodology underpinned by empirical data gathered from participating Small and Medium-Sized Enterprises (SMEs) and topical experts met during the projects’ implementation and study visits. The present multi-project applied research reduces the research-to-practice gap pertaining to the so far underestimated role of CCIs for supporting traditional SMEs in the implementation of their sustainable ideas. Once engaged into cross-sectoral collaboration with traditional SMEs, CCIs become important brokers—sustainable innovation drivers and enablers within regional ecosystems through contribution to environmentally responsible, socially equitable and economically feasible solutions for the business they work with. Thus, on the one hand, CCIs support SMEs in their transition towards more sustainable managerial performance. On the other hand, CCIs overcome disconnection and increase their recognition through new collaboration opportunities, thus providing them with new capitalization avenues on the regional and international level.