Sandström, who competes for Piteå Elit SK , took part in the Nordic Scandinavian Cup for the first time in Östersund in January 2013 , finishing in 178th place in the sprint and 50th place in the 15 km freestyle. At the Nordic Junior World Ski Championships 2015 in Almaty , he achieved 33rd place over 10 km freestyle. The following year he came at the U23 World Championships in Râşnov on 18th place over 15 km freestyle, 15th place over 15 km classic and tenth place in the sprint. He ran his first World Cup race in Falun in February 2016 , which he finished classically in 70th place over 10 km. At the 2017 U23 World Championships in Soldier Hollow , he finished 29th in the sprint, 20th in the 15 km freestyle and 18th in the skiathlon . In the 2017/18 season he made it into the points six times in the Scandinavian Cup and thus reached 27th place in the overall standings. At the U23 World Championships 2018 in Goms , he ran to 28th place in sprint, 18th place over 15 km classic and 17th place in skiathlon. In March 2018, he scored his first World Cup points in Oslo with 26th place in the 50 km mass start race. At the Nordic World Ski Championships in 2019 in Seefeld in Tirol , he finished 45th in the skiathlon and 44th in the 50 km mass start race.
Sweden