Rabbatts was born in Kingston, Jamaica in 1955 and moved to England at the age of three. She was educated at the London School of Economics and became a barrister in 1981. From 1987, she worked in local government, until 1989 when she became Deputy Chief Executive of Hammersmith and Fulham. She then became Chief Executive of Merton before being appointed to the post of Chief Executive of Lambeth in 1995. Under her charge, Lambeth did not entirely shed its image of a poorly-run council but was seen as more forward-thinking, dynamic and youthful. There were significant improvements in housing, education and council tax collection.
Upon leaving Lambeth, in March 2000, Rabbatts became Chief Executive of iMPOWER, a public sector consultancy, which she founded. She subsequently became co-chair of iMPOWER and moved on to be Managing Director of Channel 4’s education programmes and business, 4Learning.
Rabbatts was a Governor of the BBC from 1999 to 2001, resigning upon her appointment to Channel 4. She is a Governor at the London School of Economics, an Associate of The King's Fund on the Board of directors at the British Council and was awarded the CBE in the 2000 New Year Honours list.
On 3 May 2006 Rabbatts was appointed as the new Executive Deputy Chair of Millwall F.C., and on 27 October 2006 she was appointed as Executive Chairwoman of Millwall Holdings plc, taking over from Peter de Savary.