Gut, who won world championship downhill silver on the same Val d'Isere piste in 2009 behind Lindsey Vonn, took advantage of an early start position to
edge Smith by 00.16 seconds and pick up her first downhill victory to go with two super-G wins in 2008 and 2011 respectively.
"I was a bit worried and didn't expect to stay in front but it's great," said Gut.
The 25-year-old Smith took a podium place for the first time in her career as Kamer finised 00.50 seconds behind Gut while French skier Marie Marchand-Arvier agonizingly missed out on the top three with a time 00.02 seconds slower than the Swiss racer.
Smith's best previous result was eighth in a super-G race in 2011.
Olympic downhill champion Vonn, suffered a spectacular crash as the American lost control on some loose snow and flew into the security nettings on just the third gate.
Gut's victory lifts her into third spot in the downhill rankings with 124 points as Vonn continues to lead on 200 points after winning the first two races of the season.
Slovenia's Tina Maze is the comfortable overall leader on 701 points with Germany's Maria Hoefl-Riesch 236 adrift and Vonn a further 51 points back as Gut climbs to fifth on 309.