Hafþór Júlíus Björnsson

Between 2004 and 2006 Hafþór played 32 games for the Icelandic junior national basketball teams. In 2006 he played 8 games with Iceland's U-18 national team in Division A of the U18 European Championship.

For the 2007–2008 season, he moved back to play for FSu Selfoss. For the season he averaged 6.7 points on 63.8% shooting, helping the team achieve promotion to the Úrvalsdeild. The troublesome ankle forced him to retire from basketball after the season at the age of 20.

Hafþór met Icelandic strongman Magnús Ver Magnússon at his gym "Jakaból" in 2008, and Magnús said that Hafþór seemed a good prospect as a strongman. Hafþór won several strongman contests in Iceland in 2010 including Strongest Man in Iceland, Iceland's Strongest Viking, Westfjords Viking, and five of six events at the OK Badur Strongman Championships.

Hafþór took part in World's Strongest Man after earning a wild card invitation to the 2011 contest. He came in sixth overall. Taking part again in ensuing years, he placed third in 2012, 2013 and 2015. He finished runner-up in 2014 event to Žydrūnas Savickas and again in the 2016 event to Brian Shaw. In 2017, Hafþór once again was Runner up, this time to Eddie Hall.

Hafþór was cast as Ser Gregor "The Mountain" Clegane for the fourth season of the HBO series Game of Thrones in August 2013. This was his first main acting role, and he is the third person to depict the character after Conan Stevens played the role in season 1 and Ian Whyte in season 2. He became the first actor to portray Clegane in more than one continuous season with his appearances in season 4, season 5, season 6 and season 7. Hafþór was cast for the role of Mongkut in the 2017 film Kickboxer: Retaliation.

Hafþór was born in Reykjavík. His father, Björn, is over 6 ft 0 in (1.83 m) in height and his mother, Ragnheiður, is of similar stature. Hafþór's grandfather, Reynir, is nearly as tall as Hafþór and "just as broad across the chest". Reynir recalled in 2014 that Hafþór worked on the family farm outside Reykjavík as a child and "was always big, even when he wasn't tall".

Hafþór played the lead role in the Philadelphia Renaissance Faire during their debut season in 2015. He appeared as "King Thor," the leader of a Viking raiding party intent on capturing the city of Amman.

In 2016, Hafþór co-founded the spirit brand Icelandic Mountain Vodka. The main focus of the company is a seven-time distilled icelandic vodka, as well as having a gin production.

In March 2017, Hafþór was diagnosed with Bell's palsy.

On March 3, 2018, Hafþór made history and broke the Elephant Bar deadlift world record with his successful 472 kg (1,041 lb) third attempt, as well as ranking 1st at the Arnold Strongman Classic 2018. The previous Elephant Bar deadlift world record was held by Jerry Pritchett at 468 kg (1,032 lb), which was set last year at the Arnold Strongman Classic 2017.