[10] He took up Glima, a traditional Icelandic form of wrestling at the age of five and later played a vast array of sports such as football, handball, gymnastics, karate, swimming and middle-distance running.

Jón Páll was invited to the World's Strongest Man for the first time in 1983, in which he emerged runner-up to Geoff Capes by one and a half points.

[14] In 1986 World's Strongest Man in Nice, France, Jón Páll won his second title, beating Capes by 4 points.

Also in 1986, Jón Páll won World Muscle Power Classic, Europe's Strongest Man and Commonwealth Highland Games.

In the same year, he wrestled English author and Guinness World Record holder Brian Sterling-Vete in an exhibition match for the TV news and print media held at Finnur Karlsson's gymnasium in Reykjavík, Iceland.

In 1987, began Jón Páll's rivalry with Bill Kazmaier who returned to strength sports following his ban from World's Strongest Man after 1982.

Kazmaier boasted some of the heaviest powerlifting lifts of that time and had made his reputation in the 1980s as "the strongest man who ever lived" by breaking numerous strongman world records.

[15] Jón Páll who turned in at his all-time heaviest bodyweight dominated the competition, winning 8 out of 10 events while breaking multiple world records in the process.

In 1990, Jón Páll came to the 1990 World's Strongest Man injured, but after a valiant fight, won the title for a record breaking fourth time.

In 1991 Jón Páll won his fifth World Muscle Power Classic, but badly injured his left arm during Nordic Strongest Man in Denmark.

In 1981 when Kazmaier traveled to Nigeria for a Highland games style strength exhibition with Douglas Edmunds, he attempted to break his own deadlift world record by pulling 415 kg (915 lb) with straps.

During his preparation for 1987 Pure Strength, Jón Páll replicated the same setup and pulled 427.5 kg (942 lb) in his gym 'Gym 80' in front of many Icelandic spectators.

Jón Páll was described in his life documentary "Larger than Life" by Geoff Capes as "a new kind of guy on the block" and by David P. Webster equally in describing him as a man who boasted pure static strength as well as versatile athletic strength in all its forms, a combination that lead to his supreme performances.

In New Hampshire, United States, there is a popular lifting stone weighing 221 kg (487 lb) named after Jón Páll which is used in some New England Highland Games.

[25] performed in official powerlifting full meets, aged 23, in single-ply equipment[1] performed as exhibition lifts – Jón Páll is also credited with the Guinness world records of being the first man to load a 150 kg (331 lb) McGlashen stone in 1986 and for lifting the world's largest whiskey bottle in 1987.