Hadid's modeling career began when she was two years old after being discovered by Paul Marciano of Guess clothing.

She started modeling with Baby Guess before stopping to concentrate on school. Hadid eventually returned to modeling in 2011.

She resumed working with Marciano, and was named the face of a Guess campaign in 2012. Hadid has shot three campaigns with Guess as an adult.

After moving to New York City and signing to IMG Models in 2013, Hadid made her New York Fashion Week debut in February 2014 walking for Desigual's show.

In the same month, she got her break in high fashion on the cover of CR Fashion Book magazine

Hadid appeared in the 2015 Pirelli calendar. In that same year, Hadid was also the brand ambassador for Australian fashion swimwear label Seafolly.

In January 2015, she was named the Daily Front Row's Model of the Year, and a Maybelline brand ambassador.

In March 2015, Hadid and her boyfriend at the time, Cody Simpson, featured as a part of fashion photographer Mario Testino project called "Towel Series."

Hadid has appeared on magazine covers, including Vogue (United States, Paris, Italy, Britain, Japan, Spain, Australia, Brazil, the Netherlands, Germany, Italy, China)

Hadid started off the Spring/Summer campaign season – starring in Fendi and Moschino campaigns

The second Tommy Hilfiger and Hadid ready-to-wear collection was presented in February 2017 for the Spring season.

Hadid was the photographer of the Versus (Versace) Spring Summer 2017 campaign which featured singer Zayn Malik and model Adwoah Aboah.

She also photographed a special summer edition of V Magazine titled Gigi's Journal, which featured Polaroids of fashion industry colleagues, celebrities and close friends.