Sullivan made his World Cup debut in December 2001, and took one victory, the renowned downhill in Chamonix, France, on January 26, 2008.

[5][6] Sullivan attained his first World Cup podium on November 24, 2007, when he finished second at the season's first downhill at Lake Louise, a good-for-gliders course in the Canadian Rockies.

His victory at Chamonix came two months later,[3] and he went on to finish fourth in the World Cup downhill standings, the best seasonal result of his career.

Sullivan was the Downhill champion at the U.S. Alpine Championships in 2007 in the Alyeska Resort in Alaska; he finished more than a full second ahead of runner-up Erik Fisher.

[citation needed] During the 2012 season, Sullivan has written columns for SKI mag.com, giving insight to life on the World Cup circuit, which includes spending Christmas in Bormio.