Compatriot and double-defending champion Francesco Friedrich took silver but Germany's hopes of a first-ever clean sweep in the event were spoiled when Michael Vogt snatched bronze for Switzerland on the final run.
Lochner has spent much of his career in the shadow of Friedrich and won two Olympic silvers behind him, but he has been the main man this season.
He sustained that form to complete a memorable double, this time helped by teammates Thorsten Margis, Jorn Wenzel and Georg Fleischhauer, who was his brakeman in the Two-Man victory.
Lochner, who started the final day 0.43 seconds ahead of Friedrich, was first out and improved that lead on his third run.
Perfect finale
Having sat back and watched his rivals avoid any major mistakes but also fail to apply any real pressure, he duly completed the final run of the Cortina track without drama to win by a huge 0.57 seconds in what he says will be his final race in the sport.
It was a remarkable fifth gold for Margis - the most by any bobsledder, after switching from pushing Friedrich previously.
"It's a little bit difficult to put that in words," he said. "One and a half years ago, Hansi (Lochner) asked me to come in his sled and we made a plan. It's quite cool if such a plan works out, and it's pretty amazing to beat the most successful bobsleigh pilot in the world for our time (Friedrich).
"I am a little bit overwhelmed with my feelings."
Friedrich was safely clear in second and his four golds and two silvers took him past Andre Lange to make him the most successful pilot in Olympic history.
Adam Ammour, the third German pilot who climbed to third on Saturday after finishing fifth in his opening run, had only a tiny cushion heading into the last run. He paid the price for some early mistakes as Vogt, by four hundredths of a second, took Switzerland’s first medal in the event since they also won bronze in 2006.