Jay competed in the juniors until 2011. Since 2011 he has mainly taken part in the Alpine Cup. He took third and second place once. He ran his first World Cup race in December 2011, which he finished with 65th place in the sprint. In December 2012 he got his first World Cup point in Canmore with 30th place in the sprint. At the 2014 Winter Olympics in Sochi , he finished 14th in the sprint. At the beginning of the 2015/16 season he achieved his first top ten placement in the individual World Cup with seventh place in the sprint in Davos . In the further course of the season he came in the points six times, including three times in the top ten and thus finished 15th in the Sprint World Cup. In January 2016 he achieved his first podium finish in the World Cup with second place in Planica together with Baptiste Gros in the team sprint. At the Nordic World Ski Championships 2017 in Lahti , he finished 30th in the sprint and 19th in the sprint at the 2019 Nordic World Ski Championships in Seefeld in Tyrol . In the 2019/20 season he won the team sprint in Dresden together with Lucas Chanavat and achieved his first podium finish in the individual World Cup in Åre with third place in the sprint.
Participation in World Championships and Olympic Winter Games