Östberg, who started for the Falun Borlange SK, made his debut in the cross-country skiing world cup in Falun in March 1998 and finished 76th in the 10 km freestyle. In 1999 he won the König-Ludwig-Lauf . He got his first World Cup points in December 1999 in Kitzbühel with 13th place in the sprint. At the beginning of the 2002/03 season he came fourth in the sprint in Düsseldorf for the first time under the top ten in the World Cup. In the further course of the season he won his only World Cup victory in the sprint in Linz and at the end of the season he finished ninth in the sprint world cup. At the Nordic World Ski Championships in 2003 in Val di Fiemme , he was ninth in the sprint. In the following season he achieved two top ten results in the individual World Cup, including a place in the sprint in Lahti and thus achieved 14th place in the sprint world cup . After fourth place in the sprint in Düsseldorf at the beginning of the 2004/05 season, he made it into the points six times and reached 12th place in the sprint world cup at the end of the season. In the 2005/06 season he finished 13th in the Sprint World Cup. He achieved four top ten placements and third place together with Mats Larsson in the team sprint in Canmore . At the 2006 Winter Olympics in Turin , he came 12th in the sprint. In the following years he achieved placements in midfield in the World Cup. He completed his last World Cup in Stockholm in February 2008 , which he finished in 68th place in the sprint.