Json Kay was born 30 December 1969 in Stretford, Manchester. In his teens, he moved with his mother, jazz singer Karen Kay, to east London. It was here that he developed an interest in hip hop, graffiti, and all the related street culture, displeasing his mother and causing many fights between them. Eventually, his mum threw Jay out of her home, at age 15. He was forced to take on a variety of jobs to try to get by, including telemarketing and selling kilts.