Rune Brattsveen competed four years in a row at Biathlon Junior World Championships between 2002 and 2005 . Things went particularly well for the Norwegian in Kościelisko in 2003 when he finished fifth in the individual, sprint and pursuit and finished fourth in the relay. The best result in an individual race he achieved a year later as fourth in the pursuit of Haute-Maurienne . His first season in the senior division he ran in 2006/07 in the European Cup, but without achieving outstanding results. At the beginning of the following season 2007/08 Brattsveen could start in the biathlon world cup for the first time . If he missed World Cup points in the 20 km individual race in 40th place, he was able to finish in the top ten in the sprint in ninth place in his second race. In the subsequent pursuit competition he finished 5th. At the Biathlon World Championships in 2008 in Östersund Brattsveen was able to qualify for four races in a strong Norwegian team. The Norwegian finished 38th in the sprint and thus won no World Cup points for the first time in this form of competition. In the pursuit he was able to improve to 15th place. In the mass start he was eleventh, with the Norwegian relay Brattsveen was able to win the silver medal behind the strong Russians. Rune Brattsveen's participation in the 2009 European Championships in Ufa, Russia, was successful . He won gold in the sprint and with the Norwegian relay, and bronze in the pursuit race.