Coddington was born on April 20, 1941 to hotelier parents on the island of Anglesey, Wales. Her interest in fashion began in her teens, when she would anxiously await the arrival of a current issue of Vogue magazine, which was at least three months outdated because she needed to order it on "rush-copy." Coddington lived many miles away from any designer shops, so Vogue was her only connection to the fashion world. She says that she loves "the whole sort of chic thing ("Italianate culture") [about Vogue] that was so entirely out of context compared to the lifestyle that [she] led." As a teen, she was pale-skinned, convent-educated and never went anywhere on her holidays, so she just looked at Vogue.
Around the age of 17, there was a Vogue model competition, and someone submitted her pictures. She ended up winning the Young Model section. She then began her modeling career for Vogue.
At the age of 26, she was in car accident that left her with head injuries and a removed eyelid, which was later reconstructed through plastic surgery.
Two years after the accident she was interviewed by British Vogue's Editor, Beatrix Miller, and was employed as a Junior Editor. After nineteen years as Photo Editor with British Vogue, she moved to New York to work for Calvin Klein. In July 1988, she joined Anna Wintour at American Vogue, where she remains the magazine's creative director.
As of January 2016, Coddington announced that she would be exiting her role as creative director at Vogue in order to pursue other projects. It was announced on May 9, 2016 that Coddington would be working with Tiffany's.
Coddington came into the public eye in 2009 with the release of The September Issue, a fly-on-the-wall documentary about the making of the September 2007 issue of Vogue. She plays a prominent role in the film as she is heavily involved in the styling and production of the issue. Her often-tense relationship with editor Anna Wintour is also highlighted.
Coddington was married in 1968 to Michael Chow, a restaurateur. They divorced a year later. She later married the photographer Willie Christie. They divorced in 1980.
She raised her nephew Tristan, since the age of 8, after the death of her sister Rosemary.
In 1986, she moved to New York to work for Calvin Klein. She has since then lived with her partner, hair stylist Didier Malige, and several cats.
In 2010, she announced plans to write a memoir with her collaborator Jay Fielden. The two had previously worked together on the 2002 photo book, Grace: Thirty Years of Fashion at Vogue. The book was reissued in by Phaidon in 2015. But after Jay took a job as the editor of Town & Country, Grace had to postpone writing the book until 2011, after she decided to write the book with Michael Roberts. The book deal is reported to be worth $1.2 million. Her memoir, Grace, was published in November 2012. In 2015, film production company A24 optioned the rights to Coddington's memoir.Coddington, Grace, Anna Wintour, André Leon Talley, John Galliano, Manolo Blahnik, and Michael Roberts. The Snippy World of New Yorker Fashion Artist Michael Roberts. Paris: Edition 7L, 2005. ISBN 978-3-865-21151-4 OCLC 62735193
Coddington, Grace, and Didier Malige. The Catwalk Cats. Paris: Edition 7L, 2006. ISBN 978-3-865-21344-0 OCLC 85892968
Coddington, Grace, and Michael Roberts. Grace: A Memoir. London: Vintage Books, 2012. ISBN 978-0-307-36276-6 OCLC 891760577
Gordon, Michael, Grace Coddington, and Heather Gordon. Vidal Sassoon: How One Man Changed the World with a Pair of Scissors. New York: Rizzoli, 2012. ISBN 978-0-847-83859-2 OCLC 783165292 Forward by Coddington.
Donovan, Terence, Diana Donovan, David Hillman, and Robin Muir. Terence Donovan Fashion. London: Art/Books, 2012. ISBN 978-1-908-97002-2 OCLC 805020848 Forward by Coddington.
Coddington, Grace Grace: The American Vogue Years. London: Phaidon Press, 2016. ISBN 978-0-714-87197-4
Coddington, Grace, Michael Roberts, Jay Fielden, and Bridget McCarthy. Grace: Thirty Years of Fashion at Vogue. London: Phaidon Press, 2015. ISBN 978-0-714-87059-5 OCLC 905521988
In the season 3 of the anthology series American Horror Story, American actress Frances Conroy interprets the iconic Myrtle Snow. The character's red hair, as well as her passion for fashion, are considered as a tribute to the ex-model Grace Coddington.