The son of Julian and Lady Caroline Faber, Faber comes from a staunchly conservative, aristocratic political family. His maternal grandfather Harold Macmillan was Prime Minister at the time of his birth. His grandmother, Lady Dorothy Cavendish, was a member of a family which included two Prime Ministers, the 4th Duke of Devonshire (1756-1757) and the 3rd Duke of Portland (1783 and 1807-1809), related by marriage to President John F. Kennedy. Faber's great-great-great-granduncle was Lord Hartington and his great-grandfather Victor Cavendish, 9th Duke of Devonshire was also statesman. His cousin Andrew Cavendish, 11th Duke of Devonshire was married to Deborah Mitford. His uncle Maurice Macmillan was a leading figure of Edward Heath's 1970s government.

Faber was educated at Summer Fields School, Summertown, then at Eton and Balliol. At Oxford, he was a member of the Bullingdon Club.

Faber worked in marketing and as a political assistant to Jeffrey Archer before entering the House of Commons in 1992 as Conservative Member of Parliament for Westbury. He was parliamentary private secretary to the Minister of State at the Foreign and Commonwealth Office, 1994 to 1996, and then to the Secretary of State for Health, from 1996 to 1997. In opposition, after the Conservatives lost the 1997 general election, he was their front bench spokesman on Foreign and Commonwealth affairs, until 1998. He served as a member of several Parliamentary Select Committees: Social Security, 1992—1997, Culture, Media and Sport, 1998 to 2001, and the Public Accounts Committee, 2000—2001.

In 1997, he was reported to be a director of Sterling Marketing, and in 1998 was a director of Freestream Aircraft.

Faber stood down from parliament at the 2001 general election, to be succeeded by fellow Conservative Andrew Murrison, when he began a new career as a writer. His book Speaking for England: Leo, Julian and John Amery, the tragedy of a political family (2005) was about his uncle by marriage, Julian Amery, his uncle's father, Leo, and brother, John, the last of whom was executed after the Second World War for high treason.

In 2009, he was appointed as head of his old prep school, Summer Fields, with effect from September 2010.

Faber married firstly Sally Gilbert, a television weather girl, and they had one son together, Henry, but later divorced, with Faber citing James Hewitt as co-respondent. He married secondly Sophie Amanda Hedley, and they have two daughters. He is a past committee member of the MCC, the governing body of the game of cricket, and a member of White's.