The present study investigates macrosegregation and solidification behavior in the autogenous gas tungsten arc welded (GTAW) joints of 250-grade maraging steel. Bead-on-plate welding trials were conducted on solution-annealed maraging steel plates using optimized parameters to achieve full penetration with uniform bead geometry. The chemical homogeneity across the weld was analyzed using scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy. Elemental compositions were measured at the top, middle, and bottom regions of the weld and across the fusion boundary and heat-affected zone (HAZ). The results revealed negligible variation in the major alloying elements (Ni, Co, Mo, Ti), indicating the absence of positive or negative macrosegregation. A quantitative line scan across the weld–HAZ interface also confirmed uniform elemental distribution with less than 1% compositional deviation. To complement the experimental observations, Scheil–Gulliver solidification simulations were carried out using Thermo-Calc software. The simulation predicted primary austenite solidification with minimal solute partitioning and no significant secondary phase formation. The close agreement between experimental and simulation results confirms that under the selected GTAW parameters, maraging 250 steel solidifies uniformly without macrosegregation, resulting in a homogeneous microstructure and uniform hardness across the weld joint.