Extended work availability (EWA) captures the experience of an employee who needs to be available for job demands during nonworking hours. It is a ubiquitous phenomenon because of the prevalent use of information and communication technology (ICT) such as mobile devices and internet services for work purposes. Although it has been found to impair employee health and well-being, evidence that delineates how to mitigate employee EWA is sparse. Thus, an important research question is: How can managers alleviate employee EWA in the ICT-prevalent work environment? Given EWA has a close connection with the time-based work–nonwork conflict, the present study addresses this question by taking a temporal lens and focusing on the roles of three time-related determinants of employee EWA. Particularly, we first include temporal leadership as a predictor of employee EWA, which concerns a particular type of time management behavior in which a manager aims at helping employees to achieve effective use of time while performing job duties. Then, we incorporate both the individual tendency to delay an intended course of action (i.e., procrastination) and the time management environment in an organization (i.e., organizational time norms) into our research model to further reveal how employee EWA could be shaped. Drawing on spillover theory, the goal of the present study was to examine the effect of temporal leadership in determining employee EWA, as well as the roles employee procrastination and organizational time norms play. Analyses of cross-sectional survey data from a sample of 240 full-time employees showed that temporal leadership has a U-shaped association (β = 0.32, p < 0.001) with employee EWA. Both employee procrastination (r = 0.40, p < 0.001) and organizational time norms (r = 0.30, p < 0.001) are positively related to employee EWA, respectively. Moreover, the U-shaped association between temporal leadership and employee EWA becomes more salient when the organizational time norms is strong, with a standardized regression coefficient of 0.24 (p < 0.05) for the interaction between temporal leadership squared and organizational time norms. These findings contribute to a more comprehensive view of how managers can alleviate employee EWA in today’s ICT-prevalent work environment.