New Zealand top executives are seldom explored, and this paper examines the role of work-life balance (WLB) on top executives’ turnover intentions, with job burnout mediating this relationship. It is expected that top executives with strong WLB will be aided with stronger wellbeing (lower burnout) and stronger work behaviours (lower turnover). Beyond these relationships, knowledge sharing culture (KSC) is included as a moderator and combined, a moderated mediation model is tested. Using data from 126 New Zealand top executives, we find that WLB negatively related to emotional exhaustion, cynicism, and turnover intentions, with cynicism fully mediating the influence of WLB on turnover intentions. A significant moderated mediation effect is found, which indicates that the indirect effect of WLB on turnover intentions through cynicism did vary, with the indirect effect diminishing as KSC becomes stronger. At levels above 0.2SD of KSC, WLB no longer has a significant effect on turnover. The findings add new insights into understanding turnover intentions in New Zealand, especially around boundary conditions of KSC, and highlight the complexity of executive talent retention.