Advanced manufacturing is a key enabler of sustainable industrial transformation, promoting resource efficiency, reduced energy consumption, and circular economy approaches. Metal additive manufacturing (AM) illustrates this potential by improving material efficiency and enabling the repair or remanufacturing of high-value components. This lecture will focus on recent advances in Directed Energy Deposition (DED), where the integration of multi-physics modelling, in situ monitoring, and data-driven optimization enhances process control, reproducibility, and qualification. Beyond technical improvements, this combined approach accelerates knowledge gain, deepening the understanding of process–structure–property relationships and supporting more sustainable innovation pathways. Case studies from the energy sectors will demonstrate how AM extends component lifetimes, reduces waste, and lowers environmental impact, positioning it as a case study of how advanced manufacturing can drive both sustainability and knowledge-based competitiveness in industry.