This paper examines how firms succeed to leverage supplier involvement in product development. The paper extends earlier work on managing supplier involvement by providing an integrated analysis of results, processes, and conditions at the level of both the individual development projects and the overall firm. Following a multiple-case study approach with theoretical sampling, the study is carried out by examining eight projects in which four manufacturers from different industries involve multiple suppliers. The findings suggest that successful supplier involvement is dependent on the coordinated design, execution, and evaluation of strategic long-term processes and operational short-term management processes and the presence of enabling factors such as a cross-functional oriented organization. The required intensity of these processes and enablers depends on contingencies such as firm size and environmental uncertainty. In contrast with previous research, we find no indications that managing supplier involvement requires a different approach in highly innovative projects compared to less-innovative projects.