By winning his ninth gold medal in the Nordic World Ski Championships in 4 × 10 km relay in Val di Fiemme 2013, he leveled[citation needed] the achievement of Bjørn Dæhlie who had been the most successful World Champion male skier up to that point.
Whilst he was still a junior, Verdens Gang newspaper reported in November 2005 that "the ski manufacturers are fighting to get Northug".
[3] Fischer won his signature, and his contract included a base salary (the first time ever for a junior), which would be multiplied by five if he made the Norwegian elite team for 2006/07, a goal he achieved.
His victories made him the first athlete ever to win five individual gold medals at the FIS Junior Nordic World Ski Championships.
Northug himself admitted he was disappointed after not getting selected, especially as he had won the double pursuit in the National Championships earlier in the year.
[9] Northug won his first gold medal at the FIS Nordic World Ski Championships in Sapporo as a member of the 4 x 10 km relay in 2007.
He was also in a good position to compete for the silver in the 30 kilometer duathlon, but he fell in the last part of the race and was disappointed to finish fifth.
[10] Northug was the runner up to the overall World Cup in the 2008/2009 season, losing to the Swiss Dario Cologna after leading before the final races.
Northug finished in an extremely disappointing 41st place in the first Cross Country event during the 2010 Winter Olympics in Vancouver, British Columbia, Canada.
For four years, until after the 2014 Winter Olympics, Northug was slated to receive a minimum of NOK 1 million annually with a prospect of getting twice that amount if his performances equalled those of his recent previous seasons.
However, he climbed the rankings and finished 2nd after winning the prestigious penultimate stage (20 km classic mass start) in Val di Fiemme.
In the Holmenkollen World Ski Championship Northug raced in five disciplines, taking 3 gold and 2 silver medals.
During the 2011 World Championship, he gained widespread international attention when he controversially crossed the finish-line sideways after decisively beating his opponents on the last leg of the 4x10 kilometre relay.
In the Season Finale in Sweden, Northug won first two stages, the prestigious classic sprint in Stockholm and freestyle prologue in Falun, then finished fourth in the penultimate stage, 15k classic mass start, and closed the season by winning the whole mini-tour.
Despite leading before the final climb up the Alpe Cermis, he lost to Sundby, who won his second TdS title in a row.
He participated and cashed (on 653rd place) in the 2010 World Series of Poker main event which he played with skiing rival Marcus Hellner.
[21] In the early hours of 4 May 2014, Northug crashed his car, an Audi A7, near his home in Byåsen, Trondheim, while driving under the influence (DUI) of alcohol.
The latter charge stemmed from Northug having claimed, in three separate police interrogations on the day of the crash, that his passenger had actually been driving the vehicle at the time of the accident.
[24] Because Northug pleaded guilty to all the charges leveled against him, he received a summary trial, which took place on 9 October 2014 at the Sør-Trøndelag District Court in Trondheim.
In addition to the prison time, Northug was fined 185,000 kr and lost his driver's license [indefinitely, or at least] for five years.
[35] The verdict said that while he was speeding, he made four video recordings—over several days—[35] for a total of 12 minutes, while commenting[37] about his own driving, as if the drivers being passed were being humiliated and put in their place.
"[38] As of June 2021, he was enrolled [as a client] at a clinic that deals with drug dependency; there he was serving his seven-month prison sentence, according to media.