Born in Drammen, Karlsen was already a child with an unusual athleticism, and his mother recorded him in photos posing to show muscles at the age of three. After seeing a photo of Arnold Schwarzenegger Karlsen decided to train for muscles and strength at age 13, and soon spent six to eight hours of his day in the gym, training, making friends and learning from the more experienced.
Powerlifting and bodybuilding
Once he started showing remarkable strength gains, Karlsen started out as a powerlifter in 1986, winning a number of titles and setting 30 Norwegian records, 3 European records, and 1 world record by 1989.
Soon after, Karlsen began pursuing a career in bodybuilding. He traveled on the road doing posing exhibitions with some bodybuilding friends to help pay the bills. Karlsen won the Mr. Norway title, and took second place at the World Games. This victory earned him his IFBB pro card in 1993 and paved the way for him to compete as a professional. Karlsen moved to California to focus on his bodybuilding career, and his first pro show was the IFBB Night of Champions. Karlsen suffered a severe muscle tear that forced him to retire from bodybuilding, and in 1996 he quickly moved on to strongman competitions.
Strongman career
Karlsen competed in one of the 1996 World's Strongest Man qualifying heats and narrowly missed qualifying for the finals. In the 1997 World's Strongest Man contest, Karlsen qualified for his first of 7 consecutive finals from 1997, 1999-2004 (did not compete in 1998). After finishing second in the Husafel Stone carry, Karlsen was leading the finals on points, but during the warm-up for the squat event, he tore his hamstring and had to withdraw from the rest of the contest.
He has a larger than life personality and, similar to his Nordic strongman predecessor Jón Páll Sigmarsson, is known for his catchphrase "Viking Power". Karlsen was featured in the 2003 Colin Bryce documentary 'The World's Strongest Arms',[2] together with fellow World's Strongest Man champion Magnus Samuelsson where they performed world class feats of strength.
Among his best lifts in his early years were a 400 kg squat, 260 kg bench press and a 412.5 kg deadlift. In an interview in 1997, he claimed his most notable feat of strength was deadlifting 400 kg for 3 repetitions.[3]
Log Press – 185 kg (408 lb) (2002 Sweden Grand Prix)
Incline Log Press – 120 kg (265 lb) x 14 reps (2002 IFSA Finland Grand Prix)
Axle Press – 170 kg (375 lb) (2002 Sweden Grand Prix)
Axle Press (for reps) – 120 kg (265 lb) x 15 reps (2000 Beauty and the Beast Strongman Challenge) (Joint-World Record)
Flintstone Press – 200 kg (441 lb) (1996 World's Strongest Man - Group 4)
Atlas Stones – 120–180 kg (265–397 lb) (5 stones) in 18.74 seconds (2005 IFSA Nordic Championships)
Húsafell Stone – 163 kg (359 lb) (87.5% of the original) for 86.66 metres (1997 World's Strongest Man)
Front hold – 30 kg (66 lb) for 69.66 seconds (2000 IFSA Grand Prix Ireland)
Crucifix hold – 25 kg (55 lb) for 63.26 seconds (2001 Europe's Strongest Man) (World Record)
Farmer's walk – 138 kg (304 lb) in each hand (70 meter course) in 22.87 seconds (2003 Finland Grand Prix)
Wheelbarrow carry – 330 kg (728 lb) for 30 metres in 19.72 s (2003 Finland Grand Prix)
Tyre flip – 520 kg (1,146 lb) for 5 times (2004 Sweden Grand Prix)
Retirement
Karlsen retired from competition in 2006, and began serving as presenter and producer of the Norwegian version of the World's Strongest Man contest and the qualifying tour Giants Live.
After retirement
Karlsen is the event organizer for the Norway's Strongest Man competition, introducing events and commentating. Karlsen was a co-commentator for the final event at the 2010 Arnold Strongman Classic. Karlsen also ran the Viking Power Challenge event in Norway, which was a part of the Super Series and later Giants Live tour for qualification into the World's Strongest Man competition.