The childhood training partners fulfilled expectations from 20 years ago, when the ski-obsessed nation spotted their potential to win the sport's biggest prize: An overall World Cup title.
Still, Hirscher's win in a testy slalom duel with Felix Neureuther sparked fury from the Germany team, and the United States and France camps.
"The most unfair nation," Germany's Alpine director said of Austrian tactics. "Ridiculous," said American Ted Ligety. Refund the 6,500 spectators, suggested one French official.
Though Neureuther fired angry words at a TV camera when finishing the first of two slalom runs, designed to suit Hirscher by an Austrian coach, he calmed later when also beaten on the decisive second run.
"The best won and it was Marcel," said Neureuther, soon 30 and denied his first season-long title. "A very, very tough end."
Barbed comments mid-race threatened to overshadow Hirscher's second slalom title, adding to his third straight overall win. The last man to do that was American Phil Mahre in 1983.
Fenninger earned her first overall title in a season with added pressure at the Sochi Olympics, where they combined to win three of Austria's Alpine table-topping nine medals.
"We were always big talents," said 25-year-old Hirscher, recalling he and 24-year-old Fenninger were picked as prospects in their home villages near Salzburg. "All the coaches, people, ski brands, everyone (was) expecting that, at the end of the day, everything will be as it is today. She will be overall World Cup champion and me as well."
Fenninger explained the special feeling skiing for Austria.
"When you are good, you are the hero of the nation," she said. "If not, you are a loser.
Hirscher smiled when asked about challenges representing his country, and what other teams see as a winning philosophy stretching the spirit of the sport.
"Perfect," he said, comparing it to playing football for England. "If you're in it, it's awesome."
Sunday's showdown had added edge one day after Neureuther helped lift good friend Ligety to the World Cup giant slalom title, at Hirscher's expense.
Then, the German's third-place finish by 0.01 second as the final racer knocked the Austrian down to fourth and into a points tie with Ligety. The American won the title on a race wins tiebreaker.
Germany team leader Wolfgang Maier revealed Sunday that Austria considered protesting Neureuther's skis which, if upheld, would have given Ligety's title to Hirscher.
"When they win everything, everything is fine," Maier said of Austria's style. "Always they are finding something to show not really good sportsmanship."
Needing to beat Neureuther over a two-run slalom, Hirscher got lucky with his team drawn to set gates for the first, and start No. 1 guaranteeing the smoothest racing surface.
Austria's nominated coach designed a tight, twisting course which ensured Hirscher's skis would dislodge and rut the soft, wet snow for others, including No. 3 Neureuther.
"Purposely trying to make it so guys would go out and it would get super-slow," Ligety said later. "Not a whole lot of integrity in that kind of strategy."
Hirscher took a 0.06 lead, which grew later to victory by 0.
Neureuther stood hunched resting on his ski poles, watching Hirscher celebrate circling the finish area pounding his chest with his right fist.
"It's fine," between us, Neureuther said, "because Marcel wasn't setting the first run today."
Olympic slalom champion Mario Matt, who edged Hirscher for gold last month, was third, trailing 1.08 behind his teammate's two-run time of 2 minutes, 7.74 seconds.
"I can understand it a bit," Hirscher said of teams' anger, and invited the International Ski Federation to examine course-setting rules.
Neureuther used an expletive to suggest it made poor viewing.
"People think that we are not good skiers," he said. "We need more people to watch TV and then our sport can survive."
Fenninger's season-ending women's GS win was less dramatic. She also used victory to overtake the pre-race standings leader, Sweden's Jessica Lindell-Vikarby.
Fenninger's two-run time of 2 minutes, 1.28 seconds was 0.25 faster than teammate Eva-Maria Brem. Lindell-Vikarby was third, 0.33 back, and hugged Fenninger when the winner celebrated by falling back on the snow.
In lighter moments, retiring racers Tanja Poutiainen of Finland and Italy's Denise Karbon wore traditional costumes to bid farewell, and Bode Miller twice hiked back uphill to pass through the notorious Austrian gates.
The American was testing skis for next season and finished his run to cheers and applause, 47.98 back. He failed to finish his second run.
Miller has two overall World Cup titles, and Hirscher joins only three others who won back-to-back-to-back.
"If I hear these names, (Ingemar) Stenmark, Mahre, (Gustav) Thoeni, it's beautiful," said Hirscher, the first from Austria to do it.