A couple of models were established to investigate the effects of welding parameters (voltage, wire feed speed, and welding speed) on the resultant mechanical properties of welding bead and welding heat input on the basis of a Box-Behnken experimental design (BBD). The three key mechanical parameters, that is, maximum displacement, peak load, and energy absorption, were processed via the technique in order of preference by similarity to ideal solution (TOPSIS) and Shannon entropy technique. After that, the correlations among the mechanical properties, welding heat input, and three technological variables in the welding process were established herein. Analysis of variance (ANOVA) implied that the heat input relied on voltage, welding speed, wire feed rate, and the interaction effects among these factors. These models act as the basis to achieve the multi-objective optimization problem by the desirability function approach. Results suggest that the welding settings favoring a robust trade-off between minimum welding heat input and maximum mechanical properties involve an intermediate value of wire feed speed, a high value of voltage, and welding speed. This welding parameter combination not only can produce an optimum welding bead with robust mechanical performances but also guarantees the goal of optimum welding heat utilization and production efficiency, in which the high level of welding speed is strongly recommended.