This work was performed to characterize the dissimilar austenitic grade SS304 L and martensitic grade creep strength of an enhanced P92 steel welded joint. The welded joint was prepared using the autogenous gas tungsten arc welding process. The welded joint was subjected to conventional heat treatment consisting of tempering at 760 °C for 2 hours, followed by air cooling and unconventional heat treatment (UHT) consisting of normalizing (1040 °C/40 min), further followed by air cooling and, finally, stabilized tempering at 760 °C for 2 hours. The heat-treated welded joint was subjected to the microstructural characterization and mechanical testing. The room temperature Charpy toughness (CT) testing for both the weld fusion zone (WFZ) and heat-affected zone, tensile testing, and hardness testing were performed to characterize the dissimilar welded joint. Stabilized microstructure associated with improved mechanical properties were observed for UHT. The CT and tensile strength were optimum for the UHT. © 2020, The Minerals, Metals & Materials Society and ASM International.