Due to its simplicity, a desirability function procedure has been widely used in multi‐objective optimization. In this study, the impact of process parameters, specifically, traverse speed, rotational speed, and stress concentration factor (hole diameter), on the mechanical properties (tensile strength and hardness value) and weld quality class of a butt joint AA6061-T6 performing friction stir welding (FSW) is experimentally investigated. The Taguchi design describes the differences in the mechanical characteristics (hardness and tensile strength) that were noticed. A Taguchi-based design has been employed for a comprehensive analysis to consider each possible combination of elements. A desirability function is adopted to optimize all the responses simultaneously.