Born in 1960, Nigella is the daughter of former Tory cabinet minister Nigel Lawson, now Lord Lawson, and the sister of Dominic Lawson, editor of London's Sunday Telegraph newspaper. She has one surviving sister, Horatia Lawson, while her older sister, Thomasina, died in 1993.

Nigella took a degree in Modern and Mediaeval Languages at Lady Margaret Hall, Oxford (where she was editor of the University magazine Isis), and next went into full-time journalism. At one time she served as deputy Literary Editor of The Sunday Times of London. Later, she became a freelance, writing for newspapers and magazines in England and North America, including a restaurant column in The Spectator and a food column in Vogue.

In 1992, she married fellow journalist John Diamond, who died of throat cancer in 2001. They have a son and a daughter, Cosima and Bruno. Since 2002, Nigella has been the partner of advertising tycoon and art collector Charles Saatchi (born 1943). They married in September, 2003, hoping for more children.

Nigella's first book, How to Eat: the Pleasures and Principles of Good Food appeared in 1998 and led to a Channel 4 television series, Nigella Bites, which itself led to a bestselling book of the same name.

Her third book was How to be a Domestic Goddess (2000). She was voted author of the year at the British Book Awards 2000. In 2002, she launched a new television series and book, Forever Summer.