Design thinking is viewed as an attractive approach to fostering innovation. Interest in this area has increased significantly in recent years, and an increasing number of firms employ this approach, especially in the early stages of the innovation process, in which context design thinking is used to gain insights into user needs and generate new ideas. However, empirical evidence regarding the timing and process associated with the deployment of design thinking during the three different phases of the innovation process (fuzzy front end, development and testing, and commercialization) remains very limited. This gap may hinder research and practical advancements regarding when and how to implement design thinking in the innovation process. We explore this problem through a case study of a leading Chinese technology firm in the refrigeration industry using a longitudinal lens. We show that when and how the firm uses the four design thinking practices—(1) user-centeredness, (2) embracing diversity, (3) visualization and (4) iteration—to enable a transition from the fuzzy front end to development and testing and ultimately to commercialize a new product. Moreover, our findings suggest that the firm needs to adapt to the changing innovation goals and dynamically adjusts the content and intensity of design thinking practices as the innovation phase progresses. These findings therefore offer practical guidance for managers adopting design thinking to promote innovation. •Adopt a longitudinal lens to reveal when and how to implement design thinking.•Design thinking can be introduced dynamically throughout the innovation process.•The emphasis of design thinking implementation varies with the phase of innovation.•Flexible deployment of design thinking practices as the innovation phases progress.•Develop a framework for design thinking implementation in innovation processes.