The 36-year-old Swiss shaded Bode Miller and Aksel Lund Svindal for only his fifth World Cup victory after 17 years on the circuit.
"To win in Kitzbuehel is always something special. You can't compare this feeling with any other victory. It's been a long time since I was last on a podium and it's great to be back on it," said Defago, whose last victory was in Bormio in December, 2011.
While his now retired compatriot Didier Cuche holds the all-time record of victories on the Streif course, Defago is also a specialist of sorts, having won the Hahnenkamm classic in 2009.
"A downhill and a Super-G victory here means a lot. I'm starting to believe that this course likes me.
"I knew there was chance today, I really had to take it," he added.
Furious about his third place in Saturday's downhill, American Miller was again frustrated, missing victory by 0.05 seconds while Norway's Svindal, the World Cup overall leader, finished 0.10 adrift in the last podium place.
"This victory comes at the right time. Next week we're at home in St Moritz and my confidence is sky high and it's also great timing for Sochi even though I'd rather not think about it," Defago said.
"I have a title to defend but I'll take each event at a time."
His return to the top of the podium came on a day when compatriot Lara Gut won a Super-G in Cortina d'Ampezzo while Stanislas Wawrinka won the Australian Open tennis.
"It's a great day for the Swiss today with Lara in Cortina and Stan at the Australian Open. It's historical in a sense."
- Sports & Recreation
- Aksel Lund Svindal
- Bode Miller