The dc potential drop (DCPD) technique has been applied to derive the J-integral versus crack growth resistance curve (J–R curve) for fracture toughness characterization of structural materials. The test matrix covered three materials including type 316LN stainless steels, Ni-based alloy 617, and one ferritic-martensitic steel, three specimen configurations including standard compact, single edge bend, and disk-shaped compact specimens, and temperatures ranging from 20 to 650°C. When compared with baseline J–R curves derived from the ASTM E1820-13 normalization method, the original J–R curves from the DCPD technique yielded much smaller J_Q values due to the influence of crack blunting, plastic deformation, etc., on potential drop. To compensate these effects, a new procedure for adjusting DCPD J–R curves was proposed. After applying the new adjustment procedure, the average difference in J_Q between the DCPD technique and the normalization method was only 5.2 % and the difference in tearing modulus was 7.4 %. These promising results demonstrate the applicability of the DCPD technique for J–R curve characterization especially in extreme environments, such as elevated temperatures, where the conventional elastic unloading compliance method faces considerable challenges.