The Austrian was quickest in both runs to finish ahead of Olympic champion Ted Ligety with a combined time of 2 minutes, 30.17 seconds.
Ligety's first time left him with too much to do, the American having found himself down in seventh at the midway point in Italy.
Though he recovered well to take the second podium spot, Hirscher's dominance went unchallenged, while Thomas Fanara was third.
It was Hirscher's third win on the Gran Risa course, leaving him just one behind Italian legend Alberto Tomba.
Hirscher is second in the overall standings, 70 points adrift of Kjetil Jansrud, who finished 14th.