<p>The dissimilar fusion welding of ferrous (SS304) and non-ferrous (Cu-T2) metals faces significant challenges for advantageous metallurgical compatibility. However, the manifested heat input by modulating arc offset creates a favorable microstructure to achieve ~ 100% joint efficiency. The variability of heat input by optimum process parameters and arc offset reaches an upright combination of microstructural and mechanical properties. With an increased arc offset (toward the Cu-side), the joint demonstrates a variation from welding to a weld-brazing mode. Accordingly, the failure mode changes from ductile to brittle fracture. With a decreasing percentage of copper in the fusion zone, the resulting microstructure improves the weld joint properties. The optimum heat input restricts the solidification cracking by producing the desired microstructure. Overall, the homogeneity of microstructure was analyzed from the perspective of pure welding to weld-brazing mode. Finally, a sound dissimilar joint was fabricated with the least microstructural non-homogeneities and the lowest number of pores.</p>