The present study investigated the effects of degree of starch gelatinization (DSG) and drying methods (FD: freeze-drying; OD: oven-drying) on the multi-scale structure of potato starch and its functionality in noodles. Potato starches with varying DSG (0–91.39%) were prepared by FD and OD and characterized by DSC, XRD, FTIR, RVA, and SEM. The short- and long-range ordered structure decreased significantly as DSG increased. Notably, OD samples showed significantly higher relative crystallinity than FD samples (18.55% vs. 10.90%). Peak, trough, and final viscosities increased, while breakdown decreased with increasing DSG. Microstructurally, FD samples exhibited fragmented flakes, whereas OD samples formed a dense and compacted solid matrix. In noodles, low-DSG FD starch significantly enhanced lightness (L* increased from 75.27 to 83.27), hardness (increased by 15.9%), gumminess, and chewiness, whereas this hardness-enhancing effect was reversed at higher DSG levels. Strong correlations were observed between DSG and structural parameters (r > 0.80). These findings demonstrate that the drying method fundamentally alters the molecular structure of partially gelatinized starch even at comparable DSG levels, and low-DSG FD starch enhanced noodle color and texture. The findings provide a scientific basis for the targeted selection of drying methods to tailor starch functionality for specific noodle applications.