As a 15-year-old Sejersted competed in FIS races from November 2009 . His first win at this level was in January 2011 in a Super-G in Hafjell . A month later he took part in the European Youth Olympic Festival in Liberec . There he won the bronze medal in slalom and finished 13th in giant slalom. In December 2012, Sejersted competed in the European Cup for the first time , but was eliminated in all three inserts in winter 2011/12. He became Norwegian junior champion in super combined in January 2012 and was part of the Norwegian team for the Junior World Championship in Roccaraso in February of the same year . There he finished eighth in the downhill and ninth in the Super-G. At the end of the season he surprisingly won the downhill championship title at the Norwegian championships. The following day he suffered a broken fibula in a fall on the combined descent.
Despite this injury, Sejersted was able to win six FIS races in the 2012/13 season. At the Junior World Championship in 2013 near Québec , he won the bronze medal in the Super-G. In the winter of 2013/14 he began to regularly score points in the European Cup, whereby a specialization in the fast disciplines finally began to emerge. At the 2014 Junior World Championships in Jasná he won the gold medal in the downhill and the silver medal in the super combined. As the reigning junior downhill world champion, he was eligible to compete in the World Cup finals in Lenzerheide on March 12, 2014 , where he immediately scored his first World Cup points with 14th place. Due to a torn cruciate ligament , which he suffered shortly before the start of the season, he was unable to contest any races in the winter of 2014/15.
In the winter of 2015/16, Sejersted was regularly used in the European Cup and achieved a total of eight placements among the top ten. On March 13, 2016, he made it into the points of a World Cup race for the second time as 18th in the Kvitfjell Super-G . At the end of the season he was Norwegian champion in this discipline. He achieved his first top 10 placement in the World Cup on December 27, 2016 with 9th place in the Super-G in Santa Caterina . A second place was added twice in the European Cup. On January 27, 2017, he fell in the European Cup downhill from Méribel and suffered an injury to the meniscus , which meant the immediate end of the season. At the beginning of the 2017/18 season, Sejersted only narrowly made it into the points in the World Cup, which is why he missed qualifying for the Winter Olympics in Pyeongchang . In the penultimate Super-G of the season in Kvitfjell, he caused a surprise with fourth place. He achieved two victories in the Euracup.
Sejersted was able to place himself in the top ten four times in the 2018/19 World Cup . His best result at the 2019 World Cup in Åre was eighth in the Super-G.
Norway
