Knowledge infusion (KI) within consultant-supplier interfaces has a significant impact on the service delivery performance (SP) of architecture, engineering, and construction (AEC) industry construction service firms (CSFs). However, despite significant consultant-supplier interactions in Tanzania, knowledge-induced SP among AEC professionals is limited, which may harm SP. The inadequacy of these CSFs to stimulate performance may be attributable to inadequate KI. Utilizing a convenience sampling technique, a survey dataset of 171 consulting CSFs in Tanzania was generated. Consequently, Structural Equation Modelling was used to hypothesize and empirically investigate the mediating role of KI in the relationship between outbound collaboration behavior (OCB) and service performance (SP) within construction service supply chains (CSSCs). The results indicate that when mediated by KI, the indirect effect between OCB and SP becomes significant and positive, whereas its direct effect is insignificant. This demonstrates that OCB has a marginal effect on SP. Theoretically, KI primarily affects the interrelationships between the relevant variables, thereby providing novel insights into practical (managerial) implications. Thus, CSFs can strengthen their KI competencies, such as adherence to material specifications, internal transforming capacity, product data, system application, and quality control, to achieve (sustained) competitive advantage among CSSCs.