The primary objective of the present paper is to explore the link between supply logistic integration, competitive performance, lean process and supply performance. To achieve our research objectives, we develop a unique model, which conceptualizes the said relationship. Porter’s value chain and the resource based views are used as theatrical lenses of the current study using Amos software package based on a data set of 220 Iraqi manufacturing firms. Structural equation modeling (SEM) is employed to analyze the dataset. The findings of the study show that the there was a positive relationship between supply logistics and competitive performance (operational) and supply performance and lean processes were partially mediating this relationship. The study also shows the importance of managing both internal (production processes) and external processes (logistics and supply chain) of firms’ operations in an integrated manner in which supply chain management acts through key internal processes to impact competitive performance. This is the first study, which uncovers what happens “in between” the incoming materials and the end outputs delivered by firms into the market. This “in between black box” is important in improving our understanding of how inbound supply activities are translated into outbound competitive performance outcomes.