She is a former Victoria's Secret Angel, co-founder and original creative director for Nylon magazine, and she is a supporter of funding for breast cancer organizations and other philanthropic charities.

"[10] She was in the Victoria's Secret catalog and in their television commercials as one of the original "Angels", along with Tyra Banks, Karen Mulder, Daniela Peštová, and Stephanie Seymour.

In 1996, Frank DeCaro of the New York Times cited Christensen, along with Linda Evangelista, Christy Turlington, Cindy Crawford, Naomi Campbell, Elle Macpherson and Claudia Schiffer, as "The Magnificent Seven".

DeCaro reflected, "Known by their first names to legions of fans, they are the supermodel legends of the modern catwalk, the girl next door pretty underneath all the paint".

[12] She walked the runway for Dolce & Gabbana and appeared in their spring/summer 2019 advertisement campaign with Carla Bruni, Eva Herzigová and Marpessa Hennink.

[16][17] Christensen created a vintage clothing line, sold in her mother's store, the Yo-Yo Second Hand Shop, in Christianshavn, Copenhagen, Denmark.

[9] Her exhibition "A Quiet Story," curated by Jim Cook, premiered at the Locus Gallery in Rotterdam, 2006,[21] and HotelArena in Amsterdam, 2007.

Her major project for the company was documenting a trip from the seaside town of Paracas to the colonial city of Cusco and the nearby Urubamba Valley.

[33] Christensen has an apartment in Copenhagen, a house in Catskill, New York, and lives in Manhattan, where she drives "the only type of car I've ever had", a Morris Minor.