Horst started her career with IMG Models before switching to Next Management in 2009.
[1] After having struggles in London and Paris, Horst moved to New York City.
[4] In 2014, Horst appeared as a rookie in the Sports Illustrated Swimsuit Issue in which her photoshoot took place in Madagascar.
[5] Horst has appeared in advertisements for Adidas,[6] Calvin Klein, Diesel, H&M, Joe Fresh, Carolina Herrera, DKNY and Donna Karan, Nine West, Emporio Armani, Levi's, Stella McCartney, Ralph Lauren, Kenzo, and Tommy Hilfiger among others.
[8] Horst is married to the American model agency director Jason Valenta.