In December 2003, coach Marit Breivik made Hammerseng captain of the team, replacing fellow Gjøvik native Else-Marthe Sørlie Lybekk. The 2003 World Championship was her first competition as captain, but Norway was not successful and finished the championship in sixth place, thus missing the opportunity to participate in the 2004 Summer Olympics. The 2004 European Championship brought her first gold medal with the team. Hammerseng saw her performance recognized as she was voted MVP and member of the All-Star Team of the tournament.