To address issues such as weld crater defects, coating burn-off and rupture, and cracking in tungsten inert gas (TIG) welded galvanized aluminum-magnesium steel plates, as well as to enhance joint strength, galvanometer-scanned laser welding (GSL) was employed for welding zinc-aluminum-magnesium coated steel plates. The GSL joints were comparatively analyzed against TIG joints. The macroscopic morphology, microstructure, and mechanical properties of the welded joints produced by the two different processes were examined using optical microscopy, scanning electron microscopy, and a tensile testing machine. The results indicate that the microstructure of the GSL weld zone consists of acicular and blocky polygonal ferrite along with a small amount of granular bainite. In contrast, the TIG weld zone microstructure comprises irregular blocky ferrite and granular bainite. Furthermore, the higher heat input of TIG welding led to the formation of a Widmanstätte structure in the weld metal. Compared to TIG joints, GSL joints exhibit significantly finer grain size and a narrower heat-affected zone, which are beneficial for improving joint performance. The tensile strengths of both GSL and TIG joints are similar to that of the base material. However, the elongation of GSL joints is approximately 6% higher than that of TIG joints, demonstrating superior ductility.