Tessa Jane Helen Douglas Palmer was born on 17 September 1947 in London, the daughter of Kenneth Nelson Veysey Palmer and Rosemary Brougham De Momet Palmer (née Douglas). She was educated at St Margaret's School for Girls, Aberdeen; the University of Aberdeen; the University of Edinburgh; and Goldsmiths College, University of London. She married Roger Jowell in 1970 (divorced 1977) and David Mills in 1979, with whom she had two children and three stepchildren.

She worked as a child care officer in Lambeth, 1969-71, and a psychiatric social worker at the Maudsley Hospital in London, 1972-4. She was assistant director of the mental health charity Mind, 1974-86; director of a community care special action project in Birmingham, 1986-90; and ran the Joseph Rowntree Foundation's community care programme while also holding a senior visiting fellowship at the King's Fund, 1990-2. During this time, she was elected to Camden Council, 1971-86, and was a Labour Party prospective parliamentary candidate in Ilford North, 1978 and 1979. In 1992, she was elected Labour MP for Dulwich (later Dulwich and West Norwood) and represented the consitutency, 1992-2015. She was an Opposition Whip, 1994-5, and Shadow Spokesperson on Health and on Women, 1995-7.

After the Labour Party won the general election in 1997, she was appointed Minister of State in the Department of Health (responsible for public health), 1997-9, and in the Department for Education and Employment, 1999; and Minister for Women, 1998-2001 and 2005-6. She was Secretary of State for Culture, Media and Sport, 2001-7; Minister for the Olympics, 2005-10; Paymaster General, 2007-10; Minister for London, 2007-8 and 2009-10; and Minister for the Cabinet Office, 2009-10.

When the Labour Party returned to opposition, she was Shadow Minister for the Cabinet Office, 2009-10 and 2011; for the Cabinet Office and London, 2010; and for the Olympics, 2010-12.

She stood down from the House of Commons and was created a life peer and member of the House of Lords in 2015. She was previously awarded a damehood in 2012.

She died on 12 May 2018.