Jon Montgomery made his international debut as 23rd in the America's Cup in December 2002. His first noteworthy placements he reached ninth and fourth in the same competition in Calgary two years later. At the Canadian Championships in 2005 he reached sixth place. In November 2005, he made four runner-up places behind Chris Hedquist in a row in the America's Cup in Park City and Calgary . He then started in the European Skeleton Cup and came third in St. Moritz and first in Winterberg and won the overall European Cup ranking for the 2005/06 season. Montgomery has been competing in the Skeleton World Cup since the 2006/07 season . In his first race in November 2006, he came in third place in Calgary and thus achieved his best result in this competition so far. In 2007 he was also the first Canadian champion. In the 2007/08 season he was able to win a World Cup race for the first time in Cesana . At the world championship he won the silver medal with the team and in the individual.
On February 20, 2010, Montgomery achieved his greatest success so far in front of a home crowd by winning the gold medal at the Olympic Games in Vancouver .
In the 2010/11 season he won the first World Cup race of the season on his home track in Whistler , but was unable to achieve a podium finish after that. In the overall classification he was ninth. At the World Championships in Königssee he was eleventh in the individual and won the bronze medal in the team competition.