In 2011, Emilen Jacquelin took part in international competitions for the first time. At the Junior World Championship 2015 held in Raubichi, the athlete won a bronze medal in the relay race 4x7, 5 km in the category to 21 years. And at the World Junior Championships in 2017 in Osrbli, the Frenchman won two gold medals: in the sprint and the pursuit race in the senior category.
In December 2017, Jacquelin made his debut in the World Cup at the stage in Ostersund. At the second stage in the Austrian Hochfilzen the sportsman in the French relay team won the third place - this is his first podium in the World Cup.