Harlow was discovered by
America's Next Top Model 
host Tyra Banks on Instagram,
and subsequently became one of
the fourteen finalists of the
twenty-first cycle in 2014.

 

Following America's Next Top Model, Harlow modeled for the Spanish clothing brand Desigual and became their official brand representative. In September 2014, she walked and closed for the clothing brand Ashish for their spring/summer 2015 collection in London Fashion Week. She has modeled for fashion magazines such as i-D and Dazed, and for the fashion website Showstudio.com. In 2015, Harlow modeled for the Italian clothing brand Diesel for its spring/summer 2015 campaign, which was shot by British fashion photographer Nick Knight

She modeled for the Spanish and Italian editions of Glamour magazine and was featured in the August/September 2015 issue of Complex magazine. She was also featured in the August 2015 issue of Cosmopolitan. She was featured on Vogue Italia's website in an interview and accompanying photo shoot. In August 2015, Harlow shot the cover of and an accompanying editorial spread in the September issue of Ebony magazine. In 2016, Harlow was featured in a commercial for Sprite, and was featured in a campaign for Swarovski.