Purpose Openness to external knowledge has recently gained popularity as a means for firms to complement and leverage internal knowledge in the pursuit of innovation outcomes. However, conflicting evidence exists regarding the role of openness in external knowledge acquisition. This paper aims to propose that openness to external knowledge has a nonlinear effect on innovation performance and that this nonlinear relationship is contingent on an ambidextrous knowledge search strategy. Design/methodology/approach Based on original large-scale survey of 246 interfirm collaborations in the high-technology industry, it is found that the impact of openness to external knowledge on innovation performance exhibits an inverted-U shape and that this relationship is affected by an ambidextrous knowledge search strategy. Findings The results indicate that an ambidextrous knowledge strategy that addresses the depth and breadth of external knowledge significantly influences a firm’s ability to derive benefits from increased openness to external knowledge. Empirically, the authors provide an original contribution to high-technology firms by exploring how and why an ambidextrous knowledge strategy can be a critical catalyst spurring innovation performance. Research limitations/implications The research scope is limited to a single industry. Further research could extend the theoretical framework to multiple industries, which may increase the likelihood of innovation theory development. Practical implications The results suggest that firms opening up the boundaries of their innovation activity to engage in external knowledge are able to leverage their in-house innovation to enhance their innovation performance. The authors advocate that in innovation management domains, greater emphasis is needed on how openness to external knowledge has more positive impacts not only on innovation performance but also on innovation implemented management. Originality/value This study is among the first to investigate the ambidextrous knowledge search effect on the external knowledge of high-technology firms. This paper contributes to the theoretical and practical literature concerning openness innovation and knowledge management by reflecting on the ambidextrous knowledge search strategy.