A classical technique specialist, Hjelmeset's biggest success is the gold medal in the 50 km event at the FIS Nordic World Ski Championships 2007 in Sapporo. At the FIS Nordic World Ski Championships he won eight medals (all in the classical style). This includes five gold medals (50 km: 2007, 4 × 10 km relay: 2001, 2005, 2007, 2009) and three bronze medals (1999: 10 km, 2001: 15 km, and 2005: 50 km).