Background: Construction firms increasingly rely on integrated digital systems to coordinate procurement and project delivery. At PT ADHI KARYA (Persero) Tbk, however, the procurement workflow remains only partially integrated, even though SAP Materials Management (MM), SAP Project System (PS), and e-Procurement are already in use. Objective: This study examines the relationships of SAP Implementation, SAP–e-Procurement Integration, and User Competence with Project Performance, with Procurement Efficiency and Information Completeness specified as intervening mechanisms. Methods: Data were obtained from 100 purposively selected SAP users through an explanatory quantitative survey. The proposed measurement and structural models were evaluated using partial least squares structural equation modeling (PLS-SEM) with SmartPLS 4. Results: Procurement Efficiency was positively associated with SAP Implementation (β = 0.319; p = 0.007), SAP–e-Procurement Integration (β = 0.321; p = 0.002), and User Competence (β = 0.241; p = 0.014). Procurement Efficiency was also positively associated with Information Completeness (β = 0.500; p < 0.001) and Project Performance (β = 0.494; p < 0.001). Information Completeness showed an additional positive association with Project Performance (β = 0.530; p < 0.001). Bootstrap estimates of the indirect effects further supported the mediating roles of Procurement Efficiency and Information Completeness. Conclusion: Project performance is strengthened when SAP and e-Procurement operate as a more integrated workflow, procurement activities are executed efficiently, information is complete and reliable, and users possess the competence required to operate the systems effectively.