Also known as Thor Björnsson, he is an actor, strongman competitor, and former professional basketball player. He was the first actor to portray the notorious Gregor Clegane in more than one season of HBO's Game of Thrones. He was named Iceland's Strongest Man five years in a row and has also been named Europe's Strongest Man twice.
He began his career playing with the FSU Selfoss professional basketball team before he suffered a knee injury at twenty and was forced to pursue his athletic career in strongman competitions.
In January 2015, he beat a 1000-year-old record at the World's Strongest Viking competition for carrying a 1,433 pound log five steps.
He has lived in Kópavogur, Iceland. He has a daughter named Theresa Líf from a previous relationship. In 2018, he married Kelsey Henson and they welcomed their first child together, a son, on September 26, 2020.