The growing demand for lightweight, cost-effective, and sustainable materials in the automotive industry has driven interest in advanced polymer-based composites and additive manufacturing. This study investigates the techno-economic feasibility and environmental impact of reinforcing waste polypropylene (PP) with recovered short carbon fibers (rSCFs) for 3D-printed automotive components such as door panels. A Techno-Economic Analysis (TEA) evaluates material and production costs, while a Life Cycle Assessment (LCA) quantifies energy consumption and CO₂ emissions. Results indicate that using rSCF-reinforced PP reduces material costs while maintaining mechanical performance, with an overall cost of $3.80 per part and a profit margin of $3.20 per unit. The economic assessment shows a net present value (NPV) of $100,480 and a payback period of 0.65 years, highlighting financial viability. The LCA reveals a 30% reduction in CO2 emissions and an 88% decrease in energy consumption compared to virgin materials, demonstrating substantial environmental benefits. Sensitivity analysis confirms that material costs and selling price are key factors influencing profitability, while energy costs and discount rates have a moderate impact. The findings support the adoption of waste polypropylene reinforced with recovered short carbon fibers (rSCF/PP) for 3D-printed automotive components, offering a sustainable and cost-effective alternative to traditional manufacturing. Future research should focus on optimizing composite properties and scaling production to enhance industrial applicability.