[1] Mulder was featured on the cover of Vogue and was also a Victoria's Secret model, making her one of the original "Angels" and the first from both the brand and from her country.
In the early 2000s, she began to speak out about the dark side of the modeling industry and the dangers faced by underage girls and young women.
[5] By her second year on the runway, Mulder was modeling for Valentino, Yves Saint Laurent, Lanvin, Christian Lacroix, Versace, and Giorgio Armani.
[10] A New York Times article from 1991 described Mulder's work schedule, detailing a typical thirteen hour day packed with obligations to Ralph Lauren, a French film crew, Anna Sui and Giorgio Sant'Angelo.
[6] Other campaigns she appeared in included Calvin Klein, Claude Montana, Ralph Lauren, Yves Saint-Laurent's Rive Gauche fragrance, as well as Guerlain, Chloé, Revlon, Jacques Fath, Gianfranco Ferré, Gianni Versace, Chanel, and Hervé Léger.
Mulder has worked with some of the most well known fashion photographers, including Javier Vallhonrat, Peter Lindbergh, Patrick Demarchelier, Bruce Weber, Helmut Newton, Max Vadukul, Gilles Bensimon, Fabrizio Ferri, Steven Meisel, Irving Penn, Robert Erdmann, and Arthur Elgort.
Her two appearances in the Sports Illustrated Swimsuit Issue in 1997 and 1998 and her poses for the Victoria's Secret catalogue increased Mulder's profile.
On 1 July 2007, Mulder returned to the catwalk at the Dior Autumn/Winter 07/08 Couture Collection in Paris, modelling alongside Naomi Campbell, Linda Evangelista, Helena Christensen, Amber Valletta, Shalom Harlow, and Stella Tennant.
[12] On 31 October 2001, Mulder was interviewed on the France 2 show Tout le monde en parle (Everyone is Talking About It) hosted by Thierry Ardisson in front of a live studio audience.
During the shows taping, Mulder claimed that various people had raped her, including police officers, politicians, members of her former agency Elite Model Management, and Albert II, Prince of Monaco.
Within hours of the interview, her sister Saskia arrived and took her to Villa Montsouris, a psychiatric hospital specializing in such disorders as depression, anxiety, and delirium, where she stayed for five months.
[16] On 10 December 2002, after suffering for years from chronic depression, Mulder went into a coma after she overdosed on sleeping pills in an apparent suicide attempt.
She was rushed to the American Hospital in Neuilly after neighbors found her passed out on the floor of the Paris apartment on exclusive Avenue Montaigne where she was staying with friends.