Cournoyer ran his first World Cup race in Nagoya in the 2011/12 season and achieved 38th place over 1000 m. Over 1500 m, he reached the podium for the first time with third place. The following season he came in second place over 1000 m in Dresden . At the 2013 World Championships in Debrecen , he won the gold medal with the relay. The following year he won the bronze medal over 500 m at the Winter Olympics in Sochi . He also took 17th place over 1000 m and sixth place with the relay. His best results at the 2014 World Championships in Montreal were 11th place over 500 m and 1000 m respectively and fifth place with the relay. In the 2014/15 season he came in second place with the relay in Seoul . After finishing second over 500 m at the World Cup in Montreal at the beginning of the 2015/16 season , he won over 1000 m in Toronto and his first World Cup victories with the relay. In the further course of the season he achieved three times third and once second place with the relay. Over 1000 m he came second and third. At the last World Cup station in Dordrecht , he took his third World Cup victory over 1000 m and finished the season in second place in the overall World Cup over 1000 m. At the 2016 World Championships in Seoul, he won the silver medal with the relay. In the following season he came under the top ten three times over 1000 m and thus reached sixth overall place in the World Cup. He won in Calgary and took third place in Gangneung . In addition, he was second with the relay in Gangneung. His best results at the 2017 World Championships in Rotterdam were tenth place over 500 m and fifth place with the relay. In the 2017/18 season he triumphed in Budapest and Dordrecht with the relay and also achieved third place with the relay in Shanghai . At the season highlight, the 2018 Winter Olympics in Pyeongchang , he won the bronze medal with the 5000 m relay. In March 2018 he won the silver medal with the relay at the World Championships in Montreal.
In the 2018/19 season Cournoyer achieved second place over 1000 m and first place with the relay in Dresden and reached eighth place in the World Cup over 1000 m at the end of the season.
Canada
