Friedrich had already taken two-man gold this weekend and followed that up in the four-man as his quartet – which also included Martin Grothkopp, Alexander Schueller and Candy Bauer – led a German one-two.
They followed up a best first-run time of 50.92seconds with the quickest run second time around as well, to take victory in a time of 1:41.88mins.
Johannes Lochner piloted the German foursome that took silver, as their first-run time of 50.98s was the second best in the field and they maintained that position.
Hunter Church took the bronze medal, the American's first-ever World Cup podium place.
Friedrich leads the overall four-man standings on 1,277 points with Lochner in second – 38 points back – while Canada's Justin Kripps is third after finishing fifth in Igls.