Traynor is the daughter of an Irish-British mother and a Nigerian father. She was raised first in an children's home and then in two white foster families, where she was physically, emotionally and sexually abused.
In early adulthood she attempted suicide and had problems with both alcohol and drugs, but has overcome those; she does not happily discuss her childhood in detail. She initially became a nurse and then studied psychology at university. One day while working as an information manager at the University of Plymouth she saw an advertisement for the Saga Prize (for a first novel by an African-British or -Irish writer).
This spurred her into writing her first, autobiographical novel, Sister Josephine, which won the prize in 1996 without having been published or even edited. Her second novel, Divine, also autobiographical, was published in 1998.
She has traced her birth father and a half-brother on the Internet.