Lars Rösti comes from St. Stephan in the canton of Bern and starts for his homeland club. He started skiing at the age of two and competed in his first races when he was six.
At the age of 16, he competed in his first FIS races in Davos . In January 2017, he made his European Cup debut in Wengen's Super-G . Two months later he went to Åre for the first time in a Junior World Championship and finished tenth in the combination as the best result . With a view to the 2017/18 season , he was accepted into the C-squad by Swiss-Ski . After he was only able to improve to a limited extent in the European Cup, he won the bronze medal in the downhill at the Junior World Championship in Davos, just three hundredths of a second behind his teammate Marco Odermatt . Another step up in the squad, he started the next season and made it to a European Cup podium for the first time as third in the downhill from Kitzbühel . At his third and last Junior World Championship in Val di Fassa , he secured the gold medal in his favorite discipline in February 2019. On March 2nd, he made his World Cup debut on the downhill from Kvitfjell and finished 31st. He won his first World Cup points eleven days later with 15th place in the Soldeu downhill .