In July 2008, Steven Meisel selected Dunn to appear on the cover of the Vogue Italia issue devoted entirely to black models.

She has been in campaigns for Ann Taylor, Burberry, Balmain, Calvin Klein, Yves Saint Laurent, DKNY, Michael Kors, John Galliano, Victoria's Secret, Tommy Hilfiger, Topshop, Kate Spade, Express, Jaeger, Rag & Bone, Gap, Aldo, Shiatzy Chen, Benetton, H&M, Banana Republic, Zalando, Free People, Selfridges, Neiman Marcus, Pepe Jeans, Liu Jo and Saks Fifth Avenue,[17] and was the face of Rihanna's collections for River Island.

She has appeared in editorials for the American, Italian, French, British, Russian, Spanish, Turkish, Japanese, Brazilian editions of Vogue, Elle, i-D, Dazed & Confused, W, Pop, Centrefold and V, among others.

[18][19] She continued to model until she was six months pregnant and couldn't fit into any of the clothes, notably walking the catwalk for the Spring 2010 Jean Paul Gaultier show, with a baby bump.

In it she spoke of encountering discrimination telling the magazine that casting agents would say clients "didn't want any more black girls".

[25] In July 2013, she received media attention for tweeting that she had been cancelled from a Dior haute couture show, "for her boobs"; rather than her skin colour – which she noted, "usually happens".

Her first role for the cosmetic company will be fronting the brand's Go Extreme Mascara, accompanied with print and television ads.

[29] Dunn signed a deal with British multinational retailer Marks & Spencer to design a kidswear clothing collection.

[30] A collaboration between Jourdan and British fashion retailer Missguided was launched in April 2017, featuring athletic wear.

[31] She appeared in a music video for Nicki Minaj entitled "Regret In Your Tears", directed by Mert and Marcus in May 2017.

[34] As of May 2015, models.com declared her a "New Super", a selection of models who are recognised as modern day supermodels; having transcended the fashion industry and established themselves as brands and celebrities.

The "Yoncé" video was directed by Ricky Saiz and features fellow models Joan Smalls and Chanel Iman.

The "XO" video was directed by Terry Richardson and features Dunn alongside Jessica White and Diandra Forres.

The web show has featured celebrity guest co-chefs, such as 2 Chainz, Wale, Karlie Kloss, Chanel Iman, Cara Delevingne and Joan Smalls.