Seabuckthorn (Hippophae rhamnoides L.) berry oil having high nutraceutical, cosmeceutical, and therapeutic activity has been extracted from dried seabuckthorn (SBT) whole berry powder using supercritical carbon dioxide (SC-CO2), a green process for extraction of bioactives. The SC-CO2 process was optimized using Box–Behnken design. Three SC-CO2 parameters namely extracting pressure, extracting temperature, and time of extraction were examined. The optimal SC-CO2 conditions were determined, and the quadratic response surfaces were drawn from the mathematical models. A maximum recovery of 85.12% tocopherol, 71.73% carotene, and an EC50 of 29.02 mg/ml (from DPPH assay) was obtained after SC-CO2 extraction at 44 °C, 345 bar, and run time of 80 min. Use of methanol as an entrainer at 30% v/w of SBT berry at optimized conditions further increased the extraction efficiency and the potency. This extract can be used for varied nutraceutical, cosmeceutical, and pharmaceutical applications.