With the growing recognition of meaningfulness at work as a key driver of employee well-being and organizational outcomes, organizations increasingly attempt to foster meaningful work. When such efforts feel inauthentic or clash with employees' own sense of meaningfulness, employees may engage in existential labor (EL), that is, the regulation of meaningfulness at work. EL can take the form of deep existential labor (DEL), where employees try to alter their internal experience, or surface existential labor (SEL), where they outwardly conform while maintaining internal inconsistency. Despite its relevance, research on EL is scarce, particularly regarding within-person dynamics linking EL to day-level outcomes, and the potential moderators of this relationship. Built on job demands and resources theory (JD-R) and based on nested data collected from 247 respondents over 4 to 5 consecutive days (1,207 day-level responses nested within individuals), this study investigates the relationship between day-level EL and daily work engagement (WE). The study also examines the cross-level moderating effect of work centrality (WC) on this relationship. Multilevel analyses were conducted using hierarchical linear modeling (HLM 8), allowing both intercepts and slopes to vary across individuals. The results show that both daily DEL and SEL are negatively related to daily WE. Additionally, WC has a cross-level buffering effect, which attenuates the negative relationship between DEL and daily WE. These findings highlight the day-level outcomes of existential labor and identify work centrality as a person-level resource that mitigates its impact, advancing the understanding of how the management of meaningfulness unfolds in daily work life.