Born Shirley Vivien Teresa Brittain, Williams was the daughter of Vera Brittain, and began her career as a journalist, having graduated from Somerville College, Oxford (where she arrived some years after her political rival Margaret Thatcher). In 1955, she married philosopher Bernard Williams. She became a Labour MP in 1964, and rose quickly to a junior ministerial position. In 1974, she became Secretary of State for Prices and Consumer Protection under Harold Wilson, and, when Wilson was replaced in 1976 by James Callaghan, she became Secretary of State for Education. In 1974, she divorced Bernard Williams, but continued to be known by her married name.
Shirley Williams' "untidy" image endeared her to many women, and she was still regarded as a future Labour leader. However, in 1981, unhappy with the influence of the far left, she resigned from the party along with Roy Jenkins, David Owen and Bill Rodgers, to form the SDP. In the same year she was elected the party's first MP. Despite becoming President of the new party, she lost her seat in 1983. The party merged with the Liberal Party in 1988, and she supported the change. She married Harvard academic Richard Neustadt, moved to the USA, and effectively retired from politics. She returned to politics as a life peer with the title Baroness Williams of Crosby in 1993, and in 2001 became the Leader of the Liberal Democrats in the House of Lords. She is on the Advisory Council of the Institute for Public Policy Research.