The hot cracking susceptibility of a new superalloy G27 was investigated by Varestraint weldability testing. The influence of pre-weld solution annealing conditions recommended by the alloy manufacturer to obtain different grain sizes (1010 °C/1 h, 1066 °C/0.5 h, and 1110 °C/1 h) for specific applications was studied. The fusion zone solidification cracking was independent of pre-weld solution annealing, and they are associated with the γ/Laves eutectic constituents. The solution-annealed material at 1010 °C/1 h showed the lowest extent of liquation cracking, while the 1110 °C/1 h condition was the most susceptible. The increased level of liquation cracking was primarily attributed to an increased grain size of pre-weld solution-annealed material. The heat-affected zone liquation cracking was identified to be caused by constitutional liquation of NbC and supersolidus melting.