<p>Achieving both high dimensional accuracy and mechanical strength in fused deposition modeling (FDM) remains a significant challenge, particularly for sustainable materials like bio-based polylactic acid (BB-PLA) which exhibits distinct thermal and mechanical behavior compared to conventional PLA. This study presents a dual-objective optimization of seven key FDM process parameters—infill percentage, layer thickness, nozzle diameter, material temperature, raster orientation, build orientation, and extruding speed—to simultaneously enhance geometric fidelity and tensile strength. A Taguchi L18 orthogonal array was employed to design experiments efficiently, and performance was evaluated using dimensional deviation metrics and standardized tensile testing. Analysis of variance identified build orientation, nozzle diameter, and infill percentage as the most influential parameters affecting both output objectives. The optimal combination—on-edge orientation, 0.5&#xa0;mm nozzle diameter, and 80% infill—yielded a maximum tensile strength of 59.84&#xa0;MPa and a minimal dimensional error of 0.16%. These findings were validated through confirmation testing and regression modeling (<i>R</i>² = 0.88), which showed high predictive accuracy. These performance enhancements were further validated through microstructural analysis, which revealed enhanced crystallinity, reduced porosity, and superior interlayer adhesion in specimens produced under optimized conditions. The results show that BB- PLA can be converted from prototyping material to a functional candidate material that can be used for precision applications as a result of strategic optimization of the process. From this research, a validated design framework to further sustainable advancements in additive manufacturing is presented that concurrently tackles discrepancies in dimensional accuracy and structural outcomes.</p>