Her father is Jonathan Guinness, 3rd Baron Moyne, the eldest son of Diana Mitford Mosley and Bryan Guinness. Diana Mitford was the daughter of David Freeman-Mitford, 2nd Baron Redesdale, the father of the Mitford sisters. Mitford divorced Guinness and married the leader of the British Union of Fascists, Sir Oswald Mosley. Daphne Guinness has said she did not know of Mosley's political affiliations, before she heard in 1980 on the BBC News that he had died.
Daphne Guinness' mother, Jonathan Guinness' second wife, was Suzanne Lisney (died 2005), of Cadaques, Spain, and Paris. When she was 13, she became aware that she had a further three half-siblings by Susan "Shoe" Taylor, her father's mistress.
As a child, she grew up in the country houses owned by her family in England and Ireland. She spent her holidays in an 18th-century former monastery in Cadaqués, Catalonia, where the neighbors included Salvador Dalí, Man Ray, Marcel Duchamp, Dieter Roth, and Richard Hamilton.
Guinness' first work in fashion was with Isabella Blow. At the request of Fashion Institute of Technology director Valerie Steele, she spent two years mounting an exhibition of a hundred displays of her clothing, which was staged within the context of her other projects, film and modelling. She has worked with Karl Lagerfeld, NARS, MAC, Akris, Gareth Pugh and Philip Treacy), working with them artistically or as a model or both.
She was a friend of the late fashion designer Alexander McQueen. Scheduled to model for charity on the runway the day his suicide was announced, Guinness veiled herself in mourning.
She designs fashion, jewelry, and perfume. Since 1994, she has been on the International Best Dressed List. In 2010, she was named in Tatler's top 10 best-dressed list. In 2011, she created a make-up line for MAC cosmetics. In January 2011, she was asked by Tom Ford to close his comeback womenswear show.
Guinness has walked in two of Naomi Campbell's Fashion for Relief shows to raise funds for disaster victims. In the same vein, in April 2008, she auctioned off part of her wardrobe, with the proceeds going to a struggling British charity called Womankind Worldwide, which deals with women's issues at home and abroad, such as domestic violence.
In June 2010, Guinness purchased at auction the entire wardrobe of Isabella Blow, her friend who committed suicide in 2007. The lot was purchased prior to an auction which was arranged at Christie's. Guinness said of the purchase, "Indeed, in many ways, the auction would not be merely a sale of clothes; it would be a sale of what was left of Issie, and the carrion crows would gather and take away her essence forever." She later announced that she would be displaying the wardrobe at Central Saint Martins and online, as well as starting a foundation to help with mental illness. Guinness also held an auction in 2012 where she raised $744,285 for the Isabella Blow Foundation. The official show, entitled "Isabella Blow: Fashion Galore," is set for display in November 2013 at Somerset House in London.
Guinness has worked as an artist, actress, model, collector and designer. Fashion photographerSteven Klein, chose Guinness for two Vogue Italia covers. In the first, she plays Jean Seberg in Romain Gary's "Les Oiseaux vont mourir au Perou" In the other, she embodies Delphine Seyrig in Alain Resnais' masterpiece, "L'Année dernière à Marienbad".
David LaChapelle chose her to appear in his Maybach advertising campaign in two pictures for the car's Zeppelin model. On another occasion, when working for LaChapelle, she spent six hours in a tank of water, immersed for up to two minutes at a time, to produce two underwater images, with one titled "Daphne Guinness in Water".
She is also featured in the series "Return to Eden", which has not yet been released.
In September 2011, more than half a million visitors attended the Alexander McQueen exhibition "Savage Beauty", at the Metropolitan Museum of Art in New York. Shortly thereafter, the Museum at the Fashion Institute of Technology devoted one of its galleries to about a hundred of Guinness' most important pieces.
On 31 January 2012, Guinness had put her art-filled Fifth Avenue apartment for sale for 14 million US dollars.
In 2011 Guinness was photographed by photographer Bryan Adams and featured on the cover of Zoo Magazine.
Guinness has produced and edited three short films :Cashback, short film nominated for an Academy Award in 2004, was later made into a feature-length version. Guinness produced this film for the photographer Sean Ellis."The Phenomenology of Body" was a hymn to the evolution of the female wardrobe over millennia, and is available on the NY Times website."Mnemosyne" was an 'anti-commercial' made to comment on the scent, "DAPHNE", that Guinness made at the request of Comme des Garçons. The film was nominated for a Webby award.
In 2011, Guinness starred in Joe Lally's film, "The Murder of Jean Seberg".
In December 2011, she was photographed, while recorded livestream, by Nick Knight of SHOWstudio.com for 36 hours, resulting in five short films which were played in the windows of the Parisian department store, Le Printemps. In several of these films, Guinness, a soprano, sang opera arias, making her public musical debut.
At the end of 2011, photographers Markus Klinko and Indrani, Guinness, and stylist GK Reid produced "The Legend of Lady White Snake", a film based on an ancient Chinese legend, where Guinness played the central role of Lady White Snake. Bernard-Henri Lévy wrote her dialogue for the film.
In 2012, Guinness starred in Shakki, a short sci-fi fiction directed by Julien Landais.
In 2013, Guinness released a music video entitled Fatal Flaw which was directed by Nick Knight.
In 2014, Guinness released a music video for the song "Evening In Space" the lead single of her debut album set to be release in September. The video was directed by David LaChapelle.
In 2014, David Barron directed a documentary filmed in Guinness' Irish home called Daphne Guinness, The Last Leveller that focuses on her musical work and personal musical tastes.
In 1985, when she moved to New York City, Guinness came to know Andy Warhol, for whom her sister Catherine had been a personal assistant for many years. In 1987, she married Spyros Niarchos, the second son of Stavros Niarchos, the shipping magnate. The couple had three children. Her settlement, obtained at the time of her 1999 divorce, is for an undisclosed sum, which was added to her Guinness inheritance.
She lives in London and Manhattan with her three children: Nicolas Stavros Niarchos (born 1989), Lex Spyros Niarchos (born 1991), and Ines Sophia Niarchos (born 1995).
She has been romantically involved with French TV philosopher Bernard-Henri Lévy for a number of years. In the February 2011 issue of Harper's Bazaar , Guinness confirmed to journalist Derek Blasberg: "He is obviously the love of my life."
In 2012, she auctioned 100 items from her wardrobe.