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.
Unerring Friedrich clinches 11th world title
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.
Friedrich on top at halfway mark of four-man World Championships
Friedrich makes it six in a row in Altenberg