The novel superalloy M647 is a nickel-based superalloy with excellent mechanical properties and good hot formability, recently developed for manufacturing aircraft engine disks. In this study, the ingot of the alloy was produced using the VIM/VAR process, and the effect of the homogenization treatment on the microstructure and hardness of the novel M647 superalloy was investigated. For this purpose, homogenization treatments were conducted at temperatures of 1100°C and 1160°C for durations of 5 and 10 hours. Additionally, both air and water cooling environments were employed to assess the impact of the cooling medium after homogenization. The results indicated that, in all the conducted homogenization cycles, white islands enriched with segregated elements and layered eutectics were eliminated. Furthermore, while the dendritic structure was maintained after homogenization at 1100°C, increasing the temperature to 1160°C for the same durations resulted in the elimination of dendrites and concurrent grain growth within the microstructure. The homogenization treatment reduced the hardness, with longer treatment times leading to a more pronounced decrease. Moreover, the most significant hardness reduction was observed in the cycle with rapid water cooling, which is attributed to the inability to re-precipitate the γ' phase following homogenization. Grain boundary locking by secondary carbide and carbonitride particles, coupled with the Zener pinning effect, was also observed in samples homogenized at higher temperatures for longer durations.