Welding processes play a significant role in many fabrication and manufacturing industries. Among various welding processes that have been developed over the years, Gas Metal Arc Welding (GMAW) or Metal Inert Gas Welding (MIG) has received a lot of interest due to its ability to weld a variety of metallic materials, easy adaptation for automation, high deposition rate, high efficiency, and low capital requirement. This study focus on the optimization of the multi-performance characteristics of MIG welded butt joint of AISI 1008 mild steel and AISI 316 austenitic stainless steel by hybrid Grey based Taguchi method. L9 Taguchi orthogonal array was adopted for the optimization of the MIG welding current, voltage and gas flow rate. The weld joint integrity has been assessed in terms of the tensile strength, yield strength, percentage elongation and Vickers microhardness of the fusion zone. Welding current of 180 A, voltage of 14 V, and gas flow rate of 19 l/min were obtained as the optimal parameter setting for the MIG welding process. The tensile strength, yield strength, percentage elongation and hardness of 559.25 MPa, 382.22 MPa, 33.34%, and 250.63 HV respectively were obtained at the optimal setting. Voltage was the most significant process parameter with 63.76% contribution for the multi-performance of the weldments. The confirmatory test was performed to validate the optimization process which proved Grey based Taguchi method to be an easy but yet effective method for multi-performance characteristics optimization of welded joints.