Cannabis sativa L. (Cannabaceae) is an important medicinal plant known for its versatile applications. While most plant parts are extensively used, cannabis roots (CRs), which contain a diverse array of bioactive metabolites (particularly triterpenoids such as friedelin and epifriedelanol) have often been overlooked and remain underutilized. Little effort has been made to develop green extraction methods to isolate these bioactive compounds from CRs. This study aimed to investigate the potential of the subcritical dimethyl ether extraction (SDMEE) and subcritical water extraction (SWE) methods for extracting triterpenoids from CRs. Multiple extraction techniques were applied to CR samples obtained from the hemp strain [Siam CA]. Subsequently, the most promising method was optimized using response surface methodology (RSM) with a central composite design (CCD). The results indicated that water–Soxhlet extraction and SWE failed to isolate any triterpenoids from the CR sample. In contrast, the SDMEE method demonstrated a chemical profile similar to that obtained using conventional solvents and was subsequently selected for optimization using RSM with CCD. The optimal conditions were achieved using DME with water as cosolvent at 80:20 w/w and a temperature of 40 °C, which resulted in a higher triterpenoid yield than that obtained via chloroform and ethanol–Soxhlet extraction. These findings suggest that the SDMEE method holds great potential for green extraction, enhancing the value of CRs and presenting opportunities for various industrial triterpenoid applications.