The factors promoting hydrogen-related intergranular (IG) fracture in the elastic and plastic regions of tempered martensitic steel were investigated. These trials performed tensile tests after freezing the hydrogen distributions through immersion in liquid nitrogen at −196 °C and thermal desorption analysis (TDA). Specimens precharged with hydrogen to concentrations of 7.4 and 5.7 ppm exhibited embrittlement based on IG fracture in the elastic and plastic regions, respectively, at room temperature (R.T.). Specimens precharged to a level of 7.4 ppm hydrogen did not exhibit embrittlement upon tensile testing in liquid nitrogen at −196 °C. However, the frozen-in hydrogen distribution generated by precharging to 7.4 ppm hydrogen followed by preloading at 1300 MPa in the elastic region at R.T. resulted in embrittlement by IG fracture even at −196 °C. In contrast, precharging to 5.7 ppm hydrogen and preloading at 1400 MPa in the plastic region produced a slight ductility loss at −196 °C but no IG fracture. The results of tensile tests after hydrogen diffusion with unloading at R.T. (at which temperature the hydrogen was able to diffuse) and TDA of the frozen-in hydrogen distributions indicated that reversible and irreversible hydrogen distribution changes occurred in the elastic and plastic regions, respectively. These data suggest that the hydrogen-related IG fracture occurs via different mechanisms in each region.