PurposeVariations of human-versus-structure and within-humans at the organizational and the project level are critical in shaping the internal arrangement for effectiveness of project-based organization’s (PBOs) governance. Recent discourse presents governmentality at the organizational level and leadership at the project level as human agency of governance, whereas governance structures to be their counterpart. However, project-level mechanisms of governmentality that can help to understand possible variations among these governance dimensions remained veiled. This study uses institutional theory to explore these internal arrangements accommodated by variations of PBOs governance dimensions at the project level.Design/methodology/approachThe study followed Eisenhardt protocols of multiple case study design using an abductive research approach. Considering the heterogeneity of governance as a phenomenon in literature, boundary conditions were established before theorizing the model of the study to avoid ambiguities and define the research scope. Five PBOs were chosen using theoretical sampling, yielding 70 interviews. Data were analyzed by constant comparison with theory, using replication logic and cross-case analysis.FindingsFindings revealed that project managers perform a buffer function for governmentality at the project level. Identified mechanisms of governmentality at the project level included two downward mechanisms, i.e. communication and informal interactions of governors, and two upward mechanisms of adaptation and reciprocity by project managers and project team members. Cross-analysis for variations among PBOs’ governance at the project level revealed seven arrangements showcasing synergies or contrasts.Originality/valueThe study adds to organizational project management literature by advancing the significance of congruence between humans and structures in project governance. Furthermore, the synchronization of the project manager’s leadership style with the governmentality approach and governance structure of PBOs is of crucial importance at the project level. Findings suggest the same by showcasing synergetic versus contrasting internal arrangements accommodated in varying PBOs governance dimensions. Implications highlight that synergies among PBOs governance dimensions and project manager’s styles can minimize conflicts and inconsistencies in governance implementation, whereas contrasts might trigger them.