Kensit was born in Hounslow, West London, England and attended Newland House School in Twickenham. She is the daughter of Margie, a publicist, and James Kensit nicknamed Jimmy The Dip, who was a friend of the notorious London gangsters the Kray twins. James served time in prison before Patsy was born and later went on to become an antiques dealer.

Kensit was brought up as a Catholic and later attended a private Catholic school, funded by her early professional work. Kensit's first tabloid-published relationship was with Spandau Ballet's Gary Kemp. At the time she was 15, he was 24.

Kensit has been married three times, and all her husbands have been musicians. In 1988 she married Dan Donovan of band Big Audio Dynamite. In 1992 she married Jim Kerr, lead singer of Simple Minds. During her second marriage she gave birth to her first child, James. In 1997 she married Liam Gallagher from Oasis. Kensit and Gallagher had a son, Lennon, named after John Lennon. They divorced i