Innovation-driven is essentially talent-driven. Inventors are primarily responsible for creating new knowledge, exploring new technologies and have become an important part of firms’ innovative talent chains. Among them, star inventors constitute a small proportion of individuals who have achieved outstanding performance in terms of the influence of their inventions in the technical field. They are the core innovative talent for creative inspiration, breakthrough technical barriers, and technological change. Star inventors can play the roles of creative leaders, technology models, and mentors to generate positive innovation effects by accelerating knowledge creation and integration and improving inventors’ cooperation efficiency based on information and collaboration mechanisms. As such, how to improve star inventors’ innovation effects has become a practical issue that needs to be solved for firms to achieve high-quality innovation and develop new productive forces. In firms, position promotion assigns inventors with expertise in research and development to serve in management positions to play the double shoulder task role, which can generate innovative incentives. However, the scarcity of management positions may lead to peer competition, inducing uncooperative behavior and mutual trust risks. This will hinder the effectiveness of the information and collaboration mechanisms and further weaken the star inventors’ innovation effects. In addition, in the situation of the double shoulder task, the pressures and conflicts between the roles of research and management may lead to limited attention bias, induce rent-seeking behavior and a sense of unfairness, and then impact the innovation effects of star inventors. Therefore, this study explores the impact of the double shoulder task on the innovation effects of star inventors. To test this hypothesis, we adopted machine learning and text mining methods to collect inventor and patent information by using web crawler technology and the Python programming language and conducted empirical tests with A-share listed technological firms. We find that bearing the double shoulder task inhibits star inventors’ innovation effects, and collaborative culture helps to relieve the inhibitory effect of the double shoulder task role. Further tests show that the impact of double shoulder tasks on star inventors’ innovation effects varies depending on the type of management position. Namely, taking an operational management position significantly weakens star inventors’ innovation effect compared to taking a technological management position. Mechanistic analysis shows that the double shoulder task role inhibits the innovation effects of star inventors by hindering their collaboration and causing human capital loss. In addition, the inhibitory effect of the double shoulder task role mainly exists in follow-up firms, in industries with lower competition, and in regions with lower levels of social trust. The main findings are still supported after considering endogeneity issues with the methods of 2SLS, PSM and other robustness tests. This study makes several contributions. Firstly, previous literature mainly focused on the role and unique values of star employees in organizations. This study pays key attention to star inventors. Based on analyzing their innovation effects, it discusses the potential role of the double shoulder task (simultaneously taking on both R&D and management positions). The findings help to deepen the understanding of the path for stimulating the value of inventor and expand the research boundary of the determinants of star inventors’ innovation effects. Secondly, job promotion is a commonly adopted way for firms to motivate inventors. Existing studies that have discussed the impact of executives’ invention experience on corporate innovation cannot dynamically present the possible influence of the double shoulder task in the group behavior of inventors. This study analyzes the influencing factors of star inventors’ innovation effects from the perspective of promotion incentives, which helps to clarify the possible economic consequences for the inventor group when star inventors enter the management layer and deepen the understanding of the micro-action mechanism of job promotion incentives in firm innovation. Thirdly, the co-opetition relationship where competition and cooperation coexist has unique value in the innovation process. This paper analyzes the internal connection between the double shoulder task and the innovation effects of star inventors from the perspective of competition, and further embeds the cooperative culture into the analysis framework to examine its competition-buffering effect.