PurposeThe impact of executive characteristics on firm internationalization has already been extensively explored. However, relatively few studies have examined the critical role of chief executive officer (CEO) personality attributes, and especially CEO openness, in firm internationalization. This research aims to deepen the understanding of firm internationalization, by exploring whether and when CEO openness influences firm internationalization.Design/methodology/approachA sample of private high-tech listed firms in China is used, with data from 2004 to 2020.FindingsBased on upper echelons theory, this study theorizes and finds that CEO openness will positively influence firm internationalization. Further, based on the behavioral theory of the firm, this study finds that the performance aspiration gap weakens the positive effect of CEO openness on firm internationalization, but also finds that the potential slack strengthens this effect.Originality/valueFirst, the study reinterprets firm internationalization strategies from the perspective of CEO openness, a personality attribute; CEO openness is an important but so far rarely discussed topic in the field of international business. Second, for the first time, problemistic search and slack search into a research framework are introduced to explore the relationship between CEO characteristics and firm internationalization. This approach can further define the boundary conditions under which CEOs can project their values, preferences and personalities into the process of formulating and implementing a firm's internationalization strategy.