Existing humility intervention studies have yielded inconsistent findings, despite prior findings that suggest a salutary influence for general humility, including on religious leaders' religiousness/spirituality (R/S). We tested a relational spirituality model (RSM) proposition that change in humility would correspond to change in self-and coregulation, as measured by differentiation and God attachment. We did so by conducting a mixed-method study with a diverse sample of emerging religious leaders attending a graduate theological school in the northeastern United States (N = 136; M age = 39.50; SD = 11.14, range = 20 -67; 43.4% female; 41.2% Black/African American). Results of a multiple simultaneous latent change score model were consistent with the RSM, as we found evidence of concurrent and conditional changes among humility, differentiation, and God attachment over the course of a humility intervention. Qualitative analyses revealed five categories of humility cultivation practices, (a) relationships with others, (b) prayer/study/worship, (c) self-reflection, (d) self-care/rest, and (e) service, and yielded evidence of intervention fidelity. Multigroup comparisons indicated that intention toward prayer/study/worship and self-care/rest practices, and following through on completing a cultivation plan moderated the associations between humility, differentiation, and God attachment. Findings suggested that an RSM theoretical framing of change in virtuousness could inform the design of humility interventions and future studies evaluating the effectiveness of those interventions.