The manufacturing economy of a nation has to be competent and sustainable to develop technology, generate employment opportunities, serve customers with innovative products at competitive prices, provide best quality and services, and participate in global trade to boost the world economy. Adoption of new technology is important for firms to remain successful and achieve sustainable competitive advantage in the production and distribution of goods/services. The purpose of this study is to explore the critical success factors (CSFs) affecting the adoption of Additive Manufacturing (AM) in mainstream manufacturing in enhancing supply chain competitiveness and sustainability. As a methodological contribution, this research uses a mixed methods' approach. An Exploratory Factor Analysis (EFA) derives five CSFs: 'customized production with speed'; 'sustainable production'; 'flexible manufacturing system (FMS) for complex products'; 'standardization in AM industry'; and 'digital skills & infrastructure’. The Analytical Hierarchic Process (AHP) shows the weights of factors. TOPSIS (Technique for order of preference by similarity to ideal solution) ranks the four manufacturing enterprises based on EFA factors. Decision Making Trial and Evaluation Laboratory (DEMATEL) establishes the cause-effect relationship among factors. This study finds that 'customized production with speed’ is the most influential causal factor and ‘sustainable production’ the main effect factor. AM adoption helps industrial sectors in advancing with new technologies, advanced materials, and organizational structures so as to enhance the competitiveness and sustainability of manufacturing supply chains. It has a great potential to reconfigure supply chain (SC) structures in such a way that sustainable competitive advantage is achieved with less lead time and negligible adverse impact on the environment.