In his early career, he finished ninth in the 30 km event at the 2003 Junior World Championships. He made his debut in the World Cup in February 2004 in Trondheim, where he finished 67th in the sprint race. He also competed in the 50 km event in Oslo the same month, where he finished 50th. In a Marathon Cup race in March 2005 in Mora, he finished sixth. Already at the 2005–06 World Cup opener in Beitostølen, in November 2005, he collected his first World Cup points with a twelfth place in the 15 km event. He followed up with a thirteenth and a fifteenth place in December, in Canmore and Nové Město respectively. In January 2006 in Lago di Tesero he finished among the top ten for the first time, with a seventh place in the 30 km event. He finished among the top five for the first time with a fourth place in March 2006 in Falun. At the 2006 Winter Olympics he finished seventeenth in the 2 × 15 km pursuit, and fifteenth in the 50 km freestyle event.[1] He also became a part of the Norwegian national cross-country skiing squad. He had been offered a team spot twice before, but rejected both times, as it would interfere with his medicine studies.[2]
In the 2006–07 World Cup he did not compete often. Except for relay events, his best placement was tenth in the 50 km event at Holmenkollen in March 2007. In the 2007–08 World Cup, however, he opened with a seventh place at Beitostølen, and recorded a ninth place in Rybinsk right before the Tour de Ski. He performed well here, with two fourth places, one sixth place and a ninth place, and he ended up in fourth in the overall standings. He recorded an eleventh and a sixteenth place in January 2008 in Canmore, and finished on the podium for the first time. He was runner-up both in Falun in February and Bormio in March. He ended eleventh in his last race for the season.[1]
The 2008–09 World Cup season was more unstable. He did finish fifth in La Clusaz in December 2008, but also recorded a 58th, 47th, and 36th place. In the 2008-09 Tour de Ski a twelfth place was his best achievement, and he ended 23rd overall. A sixth place in Rybinsk in January 2009 followed, and at the Nordic World Ski Championships 2009 he finished fourteenth in the 2 × 15 km pursuit, and twentieth in the 50 km freestyle event. The rest of his World Cup showings that season, including the World Cup finale in Sweden, were poor. He opened the 2009–10 World Cup season with a relay race in Beitostølen.[1]
At the 2010 Winter Olympics, Gjerdalen finished 19th in the 30 km mixed pursuit and 28th in the 15 km events.
^ abKirkebøen, Stein Erik (8 May 2006). "Endelig tid til landslaget". Aftenposten (in Norwegian). Archived from the original on 4 June 2011. Retrieved 29 November 2009.
