Her father was the renowned screenwriter and film producer Carl Foreman (1914-1984) who had to move to England in order to work after being blacklisted by the Hollywood movie studio bosses during the McCarthyism of the 1950s.
Amanda Foreman was educated at Sarah Lawrence College in Yonkers, New York then at Columbia University before returning to England when she was awarded the 1993 “Henrietta Jex Blake Senior Scholarship” at Lady Margaret Hall, Oxford. At Oxford she completed an MPhil thesis Politics or providence?: Why the Houses of Parliament voted to abolish the slave trade in 1807 (1993) and a DPhil with her thesis The political life of Georgiana, Duchess of Devonshire, 1757-1806 (1998).
She remained at Oxford as a researcher, and in 1998, she published her first book, Georgiana, Duchess of Devonshire, based on her doctoral thesis. Published by HarperCollins in the UK and Random House in the U.S., the book received wide critical acclaim and won the 1998 Whitbread Prize for Best Biography. The book has been the subject of a television documentary, a highly successful radio play, starring Judi Dench, and a film, The Duchess, starring Ralph Fiennes and Keira Knightley.
Foreman has dual citizenship, maintains homes in New York City and London and writes regularly for newspapers and magazines in both countries. Since marrying Jonathan Barton in 2000, she has given birth to five children: Helena (2002), Theodore (2003), Halcyon (2005), Xanthe (2007) and Hero (2007). She is currently researching and writing a history of British volunteers in the American Civil War. The project has the title Our American Cousins.
Contrary to popular myth, Foreman did not pose naked for Tatler Magazine to publicize the launch of her first book. In 1999, almost a year after the book's publication, Foreman appeared in an article "50 notable under-forties". The subjects were photographed nude in order to reveal their essential talents. Foreman was placed behind a tall column built of copies of her book.