Active in strongman from 2017 to 2022, Kristján Níelsson competed at the highest international level. He finished 10th at World’s Strongest Man 2019 and 13th in 2021. Níelsson deadlifted 425kg at the 2020 Arnold Classic Europe and set a personal best log press of 192kg at Iceland’s Strongest Man 2021. He won the 2019 Iceland’s Strongest Man title and was known for his speed in the atlas stones, completing a five-stone run in 19.8 seconds at the 2020 Strongman Champions League.