Stefan Matter made his debut in the Telemark World Cup on March 18, 2014 in Funäsdalen, Sweden . As 21st of the sprint competition, he immediately scored World Cup points. He also took part in the remaining World Cup stations in Geilo and Rjukan this season . At the end of the season he finished 34th in the overall World Cup with 52 points. In 2014/15 Matter was part of the regular cast of the Swiss World Cup team and therefore also competed in the 2015 Telemark World Championship in Steamboat Springs, USA . His best result in the title fights was a seventh place in the Classic. In the World Cup he was twelfth overall.
In the following season he made his breakthrough to the top of the Telemark World Cup. In a parallel sprint as part of the World Cup opener in Hintertux, he achieved his first podium placement in this competition series as third. As a result, he was able to regularly rank among the top ten athletes. At the end of the season he finished fourth in the overall standings with four podium places. In 2016/17 he was among the best in his sport and achieved his first World Cup victory in a parallel sprint in Krvavec, Slovenia on January 28, 2017 . He finished the year again in fourth place in the overall World Cup, and also came second in the individual standings in the parallel sprint. His greatest sporting success to date came after the World Cup season at the Telemark World Championships 2017 in La Plagne . After becoming world champion in the mixed team parallel sprint together with Amélie Reymond and Bastien Dayer on March 15, 2017 and eliminated in the individual parallel sprint in the round of 16, he also became world champion in the Classic on March 17, 2017. In the sprint a day later, he narrowly missed another medal in fourth place.
After winning the silver medal in the sprint at the Swiss Championships in Telemark 2017 , Matter started the 2017/18 World Cup season on December 1, 2017 with a second place in the Hintertux sprint . In the further course of the season he was able to win two competitions: the Classic in Pralognan-la-Vanoise on January 13, 2018 and - as in the previous year - the parallel sprint in Krvavec on February 8, 2018. On February 17, 2018 he was in Sörenberg Swiss champion in sprint. In the overall World Cup he placed fourth for the third time in a row and also won the small crystal ball in the Classic World Cup tied with his compatriot Nicolas Michel . In 2019 , the World Cup was held for the first time since 2012 within the same calendar year. Matter achieved three daily victories: on January 26, 2019 in the Classic from Pralognan-la-Vanoise, three days later in the Classic from Pra-Loup and on February 17, 2019 in the sprint from Krvavec. He ended the season behind the Norwegian Trym Nygaard Løken in second place in the overall World Cup. In addition, he again won the discipline World Cup in the Classic and came second in the Sprint World Cup. At the Telemark World Championship 2019 in Rjukan, he became double world champion like two years before: On March 21, 2019 in the mixed-team parallel sprint in the same line-up as in 2017 and a day later in the sprint. At the Swiss Championships on March 30, 2019, he also won the silver medal in the sprint.