The Technology Readiness Level (TRL), which is a research and development stage, is an indicator of the maturity of technology and is used to judge the progress of research and technology. As the TRL stage increases, the development is completed and the level of commercialization is nearing completion. During this process, design intervention is acting as an essential element in commercialization and technology transfer, unlike in the past. In particular, the definition of design concepts and detailed design elements must be made at the prototyping stage of TRL stage 3, which is very advantageous for future technology commercialization. Accordingly, we analyzed the impact and success factors of design by reviewing major domestic and international cases that achieved results through design in various research and development fields (6T) and research purposes. In addition, we investigated the contribution of design through interviews with experts in the field of advanced industrial technology (IT, ET, etc.) using the Good Design evaluation index. In particular, we specified the role of design applicable to each TRL stage based on the design process and presented specific methods such as the definition of design specifications. In conclusion, we have once again confirmed that recognizing the need for designers' active participation in R&D projects and establishing a convergence process centered on commercialization through design convergence are very important factors in creating R&D results.