Background/Objectives: Spiritual care is core to holistic patient care, yet a persistent implementation gap exists in Chinese hospitals. This study examines the association between spiritual leadership and nurses’ spiritual care behavior, with career calling as mediator and empathy as moderator. Methods: A cross-sectional design was adopted. Data were collected from 323 frontline nurses in 10 public hospitals across five provinces in China from June to September 2025 using validated Likert scales. Analyses included confirmatory factor analysis, hierarchical regression, and a second-stage moderated mediation model with 5000 bootstrap resamples using SPSS 26.0 and Mplus 8.3. Results: Spiritual leadership was positively associated with both nurses’ spiritual care behavior and career calling. Career calling partially mediated the relationship between spiritual leadership and nurses’ spiritual care behavior. Furthermore, empathy significantly strengthened the positive association between career calling and spiritual care behavior, and amplified the indirect effect of spiritual leadership on nurses’ spiritual care behavior via career calling. Conclusions: Spiritual leadership, career calling, and empathy are key factors associated with nurses’ spiritual care delivery. Targeted interventions for these factors can bridge the spiritual care implementation gap and enhance holistic patient care.