Fielding (born 19 February 1958) grew up in Morley, West Yorkshire, a textile town on the outskirts of Leeds in the north of England and attended Wakefield Girls High School. She lived next to a Factory that made the fabric for miners’ donkey jackets, where her father was Managing Director. Her father died in 1982. Her mother, Nellie, still lives in Yorkshire and she has three siblings, Jane, David and Richard. Fielding studied English at St. Anne's College, Oxford and was part of the Oxford revue at the 1978 Edinburgh Festival, where she formed a continuing friendship with a group of comic performers and writers including Richard Curtis and Rowan Atkinson.

Fielding began work at the BBC in 1979 as a regional researcher on the BBC news magazine Nationwide and then worked as a Production Manager on various children’s and light entertainment shows. In 1985 Fielding produced a live satellite broadcast from a refugee camp in Eastern Sudan for the launch of Comic Relief. She wrote and produced documentaries in Africa for the first two Comic Relief fundraising broadcasts. In 1989 she was a researcher on the Thames TV documentary “Where Hunger is a Weapon” about the Southern Sudan rebel war. These experiences formed the basis for her first novel Cause Celeb.

From 1990 - 99 she worked as a journalist and columnist on several London newspapers including the Sunday Times, The Independent and The Telegraph. Her next work Bridget Jones's Diary began its life as an anonymous column in The Independent in 1995. The success of the column lead to two novels and their movie adaptations. Fielding was part of the scriptwriting team for both.

Fielding divides her time between London and Los Angeles. She and The Simpsons writer/executive producer Kevin Curran began a relationship around 1999 and Fielding has two children by him: Dash, born in February 2004, and Romy born in July 2006. However, she and Curran broke up in 2009.

Fielding’s first novel, Cause Celeb was published in 1994 to great reviews but limited sales. She was struggling to make ends meet while working on her second novel, a satire about cultural divides in the Caribbean when she was approached by London’s The Independent newspaper to write a column as herself about single life in London. Fielding rejected this idea as too embarrassing and exposing and offered instead to create an imaginary, exaggerated, comic character. Writing anonymously, she felt freed up to be honest about the preoccupations of single girls in their thirties. It quickly acquired a following, her identity was revealed and her publishers asked her to replace her novel about the Caribbean by a novel on Bridget Jones’s Diary. The hardback was published in 1996 to good reviews but modest sales. Word of mouth spread, however and the paperback, published in 1997 went straight to the top of the bestseller chart, stayed there for over six months and went on to become a worldwide bestseller. The diary - starting each day with its signature list of calories, alcohol and cigarette intake, is credited with spawning a new confessional literary genre in the form of Chick Lit.Fielding continued her columns in The Independent, and then The Daily Telegraph until 1997, publishing a second Bridget novel The Edge of Reason in November 1999. The movie of Bridget Jones’s Diary was released in 2000 and the movie of the sequel in 2004. In 2005 Fielding began the further adventures of Bridget Jones in The Independent. A third Bridget Jones movie is planned and Fielding is currently at work on the book and lyrics of the musical stage version of Bridget Jones’s Diary..

Fielding credits Bridget’s success to the fact that it is about more than just single life, but “the gap between how we feel we are expected to be and how we actually are” which she has described as an alarming symptom of the media age.

• Cause Celeb (1994) is a satire, based on the relationship between celebrities and refugees set in a camp in a fictional country in East Africa.
• Bridget Jones's Diary (1996)
• The Edge of Reason (1999)
• Olivia Joules and The Overactive Imagination (2003) a comic spy novel set in Miami, Los Angeles, England and the Sudan .

Short stories

• Ox-tales (2009) a collection of short stories in aid of Oxfam