PurposeThis article aims to examine the impact of leadership styles on new product development (NPD) and how product innovativeness of NPD projects moderates this impact. The results reveal the implications of different product innovativeness for leaders of NPD projects in achieving successful outcomes.Design/methodology/approachData were collected through a questionnaire survey of NPD team members who were involved in NPD. Participants were employees from different departments, including research and development (R&D), quality control (QC), production and marketing. These individuals worked in innovative manufacturing industries such as automotive and auto parts and electronics.FindingsResults show that transformational leadership has a significantly positive effect on new product success and NPD speed, whereas transactional leadership has a significantly negative effect on both outcomes. Furthermore, the positive impact of transformational leadership on new product success for high innovativeness is stronger than for low innovativeness. In addition, the negative impact of transactional leadership on both new product success and speed for high innovativeness is stronger than for low innovativeness.Research limitations/implicationsFirst, the sample size was fairly small because of limited access to middle-level management and low willingness to share information involving the firms' production. Second, since both transformational and transactional leaderships are multidimensional, each dimension may affect performance in different ways. Third, the respondents were mainly from a single department which could omit varying perspectives.Practical implicationsThe research findings provide recommendations on how different leadership styles support team members to effectively perform NPD tasks in either high or low innovativeness.Originality/valueThis study extends the theory of leadership by providing a holistic understanding of how leadership styles affect NPD performance. It also extends the understanding of how the impact of two different leadership styles on NPD performance is moderated by product innovativeness.