Polylactic acid (PLA), a biodegradable thermoplastic derived from renewable resources, has emerged as one of the most widely utilized materials in fused deposition modeling (FDM) due to its printability, cost-effectiveness, and environmental sustainability. Despite its popularity, PLA parts fabricated by FDM often suffer from reduced mechanical reliability as a result of anisotropy and processing variability. This study presents a comprehensive experimental and numerical investigation into the strain-rate-dependent mechanical behavior of FDM-printed PLA components, with particular emphasis on the influence of build orientation, raster angle, and infill pattern on tensile performance. ASTM D638 Type-V dog-bone specimens were fabricated using Ender 3 Pro and Xplorer 3D printers and tested at strain rates of 2 mm/s, 5 mm/s, and 10 mm/s on a Universal Testing Machine. Results revealed that tensile strength increases significantly with higher strain rates, showing improvements of up to 115%, though at the expense of ductility. Among orientations, on-edge samples exhibited the highest strength of 32.3 MPa, while raster angles aligned with the loading axis enhanced stress transfer and stiffness. Infill geometry further influenced energy absorption, with concentric patterns outperforming hexagonal arrangements. Numerical simulations conducted in Ansys and Abaqus correlated well with experimental findings, validating stress–strain responses and failure trends. The combined insights demonstrate the critical role of process parameters in tailoring the mechanical properties of FDM-printed PLA parts.