Hosk was born in Stockholm on 7 November 1988[12] in Stockholm.[13] Growing up in Sweden, Hosk was presented with offers to model during high school after her father submitted photographs to various modeling agencies in Sweden when she was 13;[6] she began modeling at 14.[5] She did some modeling in high school but decided to primarily concentrate on her studies instead (she did some notable work with Guess and other companies however). After graduating, she decided to pursue a career in the Swedish women's basketball league. Hosk has commented that the level of play in the Swedish professional basketball league was not on par with the WNBA, and that interest in the sport was not as great in Sweden as in the United States. Although she ultimately abandoned professional basketball for modeling, Hosk has said that the intense rigor of practices (8 per week when playing basketball) and travel helped prepare her for the physical and travel demands of the modeling world.[10]
After playing professional basketball for two years, she began receiving many job offers and soon moved to New York City to begin modeling full-time. Some writers have speculated that her work with Victoria's Secret was what brought her into the top tier fashion world, but Hosk also identifies her work with photographer Ellen von Unwerth in campaigns for Guess.[8]
Hosk is the daughter of Swedish father Pål and Finnish mother Marja. She has two brothers.[6] Her cousin, Alice Herbst, is also a model. Herbst won the televised competition of Sweden's Next Top Model in 2012.[17]
Hosk has worked to support the anti-human trafficking organization, FAIR Girls. She became interested in the issue after seeing the movie The Whistleblower, which dealt with issues of sex trafficking.[8]
Though the media often notes her physical resemblance and nominal correlation to Queen Elsa from Disney's 2013 film Frozen, she denies any connection to the character or media franchise.[18][19][20]
Since the beginning of 2015, she's in a relationship with British businessman Tom Daly.[21] Their daughter was born on February 11, 2021.[22]