Gas metal arc welding (GMAW)-based wire-arc additive manufacturing (WAAM) method has gained popularity due to exhibition of better features like effortlessness in deposition of material at a higher rate and fabrication of multi-walled components with minimum cost. The additive components of stainless steels have gained a lot attention for multiple applications owing to their favourable characteristics such as excellent strength, high resistance to rust and corrosion, durability, and aesthetic nature. GMAW method requires a systematic approach to control input variables to built a multi-walled component. Thus, the present has made an attempt to attain the appropriate process conditions for bead morphologies of bead height (BH), and bead width (BW). GMAW process was employed for single-layer depositions by considering voltage, gas mixture ratio, and travel speed as design variables. SS309L was used as filler wire material with SS316L material as substrate plate. Box–Behnken technique of RSM has been used to design a systematic planning of experimentation. The obtained results were analysed by using ANOVA, normal probability plots, and main effect plots. Empirical relations were also developed between design variables and output measures. Author believes the current study will be suitable for researchers as starting point to select appropriate design variables.