All the latest on the world's youngest royals
Over the years, she has earned respect not only for tackling some daunting problems head-on, but also for creating an admirable role model as a divorcée by staying on such excellent terms with her ex-husband, Prince Andrew.
Sarah was born in London in 1959 to parents Major Ronald Ferguson and his wife Susan. As a child she loved horse riding and won many cups and shows. In 1972, her parents separated and her mother married for the second time to an Argentinian, Hector Barrantes, then moved to South America.
After graduating from Queen's Secretarial College at the age of 18, Sarah went to work in a public relations firm in London. In 1985 she was invited to a house party at Windsor Castle to celebrate Royal Ascot, and although she already knew Prince Andrew from childhood, it was here that a romance developed out of their friendship.
After she accepted Prince Andrew's proposal in a Scottish stately home, the couple were married on July 23, 1986, at Westminster Abbey, with a billion people tuning in to watch the televised nuptials. Sarah and Andrew have two children, Princess Beatrice and Princess Eugenie, born in 1988 and 1990 respectively.
At first, the exuberant Sarah was popular in the press and was frequently seen out with her sister-in-law Princess Diana. However, she soon started to receive criticism and, with a husband in the Navy whom she saw infrequently, life became increasingly miserable.
She turned to writing, and published a series of children's books about Budgie The Helicopter. Despite their success, the Duchess found herself heavily in debt as a result of her jet-set lifestyle. In 1992, she separated from the Duke, just five months after photographs were published showing her caught in a 'compromising position' with financial advisor John Bryan.
Although Sarah and Andrew divorced in 1996, they continued to share a house together near Ascot for many years and Sarah, who has been in the past been linked to Italian aristocrat Count Gaddo della Gherardesca, describes her ex-husband as her "bestest friend".
At one point, the Duchess' stock could not have fallen any lower. Pilloried by the press, she was forced to cope with a very public banishment from the royal family, on top of debts of £4 million. But she has survived it all and come back stronger. She is the US spokesman for WeightWatchers, has stood in for CNN's Larry King when he goes on holiday, and fronts a publicity campaign for a financial advisory company no mean feat by any standards.
The title of one of her many books: Reinventing Yourself With The Duchess Of York summed up her philosophy of getting on with the show. Now a millionairess in her own right she is able to devote more time than ever to her charity work including Children in Crisis which she founded in 1993 and working as a patron for the Teenage Cancer Trust among many other kids' charities.
Her relationship with her daughters has developed since her divorce to one of close friendship and companionship. In 2006 she declared they were all "totally and utterly connected in every way." It is hard to miss the pride she feels for them but they, too, have been quick to praise their famous mum. On her 18th birthday, Beatrice said Fergie was the one who inspired her most. "She leads by example and her behaviour is one that I'd really like to follow", she said.
The duchess and her eldest daughter have been known to act as each other's 'date' on the social scene and in 2006 the pair partied with P Diddy in Saint Tropez alongside Paris Hilton and attended the Beckhams' World Cup bash together. Sarah has become a bona fide celebrity in the US, even wooed by reality TV shows, and has made firm friends among the glitterati both there and in the UK. She keeps her commerical actvities, which have included promoting various products including Wegewood china, to the States though for fear of upsetting the Royal Family.
Her relationship with the British monarchy has steadily improved much to her delight. "The Queen is one of the finest ladies I've ever met in my life," she told an American publication in January 2007. "I'm so honoured to be able to say we are friends. I love her. She's given up her whole life to her country. She's a great lady and a wonderful grandmother."
However, her relationship with her former in-laws was put under strain in May 2010, when Sarah was taped allegedly offering access to her former husband, Prince Andrew, in exchange for money.
She issued a statement saying she was "sincerely sorry" for her actions and admitted that her finances had been under strain after a British newspaper filmed her taking a cash down payment as part of a £500,000 deal.
All the latest on the world's youngest royals