Feuz, of Switzerland, clocked a winning time of one minute 43.76 sec. on an emotional day of skiing as the racers honored Poisson by wearing bibs with his name and heart-shaped stickers bearing his initials on their helmets.
"Everything worked out perfectly today for me," said Feuz. "It was really nice to see that the whole ski family stood together and that the French team participated today. The sticker and the bib was a beautiful gesture."
Feuz edged runner-up Matthias Mayer of Austria by just under a tenth of a second while Norway's Aksel Lund Svindal was third in 1:44.08.
Adrien Theaux was the fastest Frenchman on Saturday, finishing in seventh place.
Svindal said race day felt different and he was inspired by the courage shown by the men's French speed team.
"It was a different atmosphere. I was cheering Adrien (Theaux). It would have been the perfect start for the French team if they got the win today," said Svindal.
"The French team did a very good job. They came here. They stayed as a team instead of going home. They showed that what happened is tragic, but we are stronger together," he said.
"It was brave, gutsy and important for all of us. Not so much the result, but being there. Them being so brave makes it easier for other teams. No one would have gained anything to cancel these races."
Poisson, a downhill bronze medallist at the 2013 World Championships, was killed after he lost a ski, went through the safety netting and struck a tree during downhill training on November 13th at nearby Nakiska ski resort in the Canadian Rockies.
The 35-year-old Poisson was travelling at more than 100 kilometers per hour (62 miles per hour) when he lost his balance on a curve.