In the most prestigious event of any Winter Olympics program, Mayer covered the treacherous course in 2:06.23 -- just .06 of a second faster than Italy's Christof Innerhofer. Norway's Kjetil Jansrud won the bronze, having been timed a mere tenth of a second slower than the winner.
American Bode Miller, who twice turned in the fastest training run in the days prior to the event, finished eighth. He was quickest at the first check point, but then clipped a gate and lost momentum in his bid to win his first Olympic downhill title.
Miller, 36, has won five Olympic medals -- including a gold in the alpine combined at Vancouver four years ago along with a bronze in the downhill. He had been trying to become the oldest winner of the highlight attraction of the Winter Games.
"It's tough. I was looking to win," Miller said. "I thought I had a good chance at it. I was well-prepared."
Mayer won his first Olympic medal, but it was the second for the Mayer family. Mayer's father, Helmut, took home the silver medal at the 1988 Calgary Olympics in the super-giant slalom.
This was the fifth time in the last 11 Olympics that an Austrian skier has won the downhill. Alpine skiing stars Tony Sailer, Egon Zimmerman and Franz Klammer are among those who have won the Olympic downhill for Austria.
The Austrians failed to win a medal of any sort in the race four years ago, only the fifth time that has happened since the downhill became part of the Olympics in 1948.
Aksel Lund Svindal of Norway finished fourth in Sunday's race and American Travis Ganong was fifth in the most significant showing of his international skiing career. Svindal was the silver-medal winner in the downhill at Vancouver.