[4] When she was three years old, the family moved to Mississauga, a suburb of Toronto, Canada, to escape the generational effects the World Wars had on them.

After switching to Elite Model Management, Werbowy landed several prominent bookings in Canada, but achieved little international success.

She gave modelling a final shot as a means to fund her art school education, saying, "I returned to New York, met my agent and the next day I had an exclusive deal with Prada.

"[6] When the Elite Toronto's head scout, Elmer Olsen, started his own agency, Werbowy followed and her career began to flourish.

In her first season, Fall/Winter 2003, Werbowy achieved two of modelling's highest feats: the cover of Vogue Italia, thrice (in July, August and October), and Prada's Fall/Winter ad campaign.

[10] She has appeared on the cover of magazines such as international editions of Vogue, Elle, Harper's Bazaar, V, W, Marie Claire, Allure, Glamour, and Numéro.

Werbowy has walked the runways for Balenciaga, Givenchy, Dior, Tom Ford, Chloé, Marc Jacobs, Gucci, Versace, Miu Miu, Alexander McQueen, Prada, John Galliano, Louis Vuitton, Yves Saint Laurent, DKNY, Ralph Lauren, Chanel, Stella McCartney, Dolce & Gabbana, Karl Lagerfeld, Carolina Herrera, La Perla, Max Mara, Calvin Klein, Missoni, Zac Posen, Moschino, Oscar De La Renta, Roberto Cavalli, Tommy Hilfiger, Valentino, Fendi, Jean Paul Gaultier, Burberry, Celine, Hermès, Michael Kors, Balmain, and Lanvin.

She has appeared in advertising campaigns for Chanel, Yves Saint Laurent, Gucci, Hermés, Prada, Missoni, Versace, Celine, Louis Vuitton, Roberto Cavalli, Valentino, Dior, Lancôme, Zara, Balmain, Jean Paul Gaultier, David Yurman, Salvatore Ferragamo, Hugo Boss, Isabel Marant, DSquared2, Loewe, Diane Von Furstenberg, Mango, Balenciaga, Tiffany & Co., AG Adriano Goldschmied, H&M, and Bloomingdale's.

Photographed by Steven Meisel, she was presented on the September 2004 cover of American Vogue as one of the "Models of the Moment".

[11] In July 2007, Forbes listed Werbowy as the ninth-highest-earning model in the world after Karolina Kurkova, Natalia Vodianova, Carolyn Murphy, Alessandra Ambrosio, Adriana Lima, Heidi Klum, Kate Moss and Gisele Bündchen.

[18] For Vogue's September 2013 issue, in homage to her personal life in Ireland, Werbowy appeared in an editorial alongside American actor Adam Driver, photographed by Annie Leibovitz.

Werbowy ranked 12th on the 2015 Forbes list of highest-paid models, having earned an estimated USD$4.5 million.

[2] In 2023, Werbowy returned to modelling for a Gucci campaign by the brand's new creative director Sabato de Sarno.