Employee agility represents an important driver of new venture performance in a highly dynamic and competitive market. We examine what factors influence employee agility in new ventures in the context of individualistic and collective cultures. Drawing on Job Demand-Resource Theory, we develop a theoretical model that explains how job autonomy among the employees of a new venture influences agility through positive work engagement. We also argue that trust in founders is crucial in enhancing the relationship between work engagement and employee agility. To test our model, we conducted two studies in cross-cultural settings. In Study 1, we collected 205 responses in a multi-wave survey circulated among employees working for startups in India (a collective culture) and in Study 2, we collected 187 survey responses in the United States of America (an individualistic culture). Our results from both studies facilitate disentangling the underlying mechanism of employee agility and show that trust in founders even indirectly moderates the relationship between job autonomy and employee agility, such that this relationship is stronger when trust in founders is high. Thus, our study allows for more accurate predictions about how employee agility emerges in new ventures. Our study contributes to research on how a founder's interpersonal relations could have an implication on employee agility in startups.