Spillane won his first championship in 2003, securing first place and the gold medal in the 7.5 km sprint event at the World Championships in Val di Fiemme. In so doing, he became the first American athlete to win a gold medal at the FIS Nordic World Ski Championships. However, an injury prevented him from defending his title at the 2005 Championships. At the 2006 Winter Olympics in Turin, Italy, Spillane finished a disappointing tenth in the 7.5 km sprint and 30th in the individual. World Championships in 2007 and 2009 would continue to be disappointing for him as he placed no higher than 16th in any event. Spillane's coaches reported that although he struggled in the latter half of the 2009 season, they expected him to be ready and competitive for the 2010 Winter Olympics in Vancouver, British Columbia, Canada.