Leo James Hagan, 20, was found guilty of involuntary manslaughter and assault after a three-day jury trial in U.S. District Court in Great Falls in February.
Federal prosecutors said Hagan and two friends had been socializing at the Trailhead Saloon in East Glacier last June and he was driving drunk when the three left and crashed on Two Medicine Road, just inside the park boundary. One victim died after being trapped under the SUV when it rolled.
Prosecutors said Hagan left the scene, and tried to say he had come upon the crash and wasn't involved.
Now, Chief U.S. District Court Judge Brian Morris has sentenced Hagan to 18 months in prison, with three years on supervised release.