Gut clocked a time of one minute 22.86 seconds at the Canadian resort, pipping Liechtenstein's Tina Weirather by just three hundredths of a second.
Austria's Anna Fenninger came third ahead of compatriot Elisabeth Goergl, with Lindsey Vonn coming in fifth as her return from serious injury continues in impressive style.
“I knew that coming to Lake Louise was not going to be easy for me”, said Gut, who now tops the overall World Cup standings despite having struggled to 10th and 13th in the weekend's other races.
“Finding the right line and pace on the downhill course is still a big mystery to me. I was hoping that with the way I have been skiing this season, things would go better. But going into the super g today was something different. I knew what to do to ski fast and it worked out."
Vonn was 0.85 seconds behind the winner, and despite still having to be tentative with her recovering knee she clearly felt that she could have been on the podium.
"I was too straight in the top section and it cost me some time,” Vonn said.
“Then I tried to be a little bit to aggressive going on to the flat. I got pretty low on the line.
"But I'm really happy with my skiing. It's getting better everyday. I know now that I can win and be on the podium. That gives me confidence and that was my goal of this weekend.
“To be honest I don't know yet what races I am going to do in Europe. My focus is on the Olympics and with my knee the way it is, I am just not sure how many races I will do.
"My goal is to put myself in the best position going into Sochi very confident and try to win. I will think about all this after this weekend and come up with a decision with my coaches."