Gavin was born in Kilburn, London England to parents Barbara and Richard. He has an older sister Soraya and a younger sister, Lorraine. His father, a doctor, and mother divorced when he was eleven years old. He went to Westminster School.
He met Nigel Pulsford in 1992 and together they formed Bush soon after.
On September 14, 2002, Gavin married Gwen Stefani, lead singer of the pop band No Doubt.