Boyd was born and spent the first six months of her life in Prestatyn, North Wales, where her father, an army major, was stationed after the war. She was later educated in London, then at the boarding school Roedean. She trained as a nurse at Great Ormond Street Hospital, London, and subsequently as a marriage guidance counsellor with Relate before reading English Literature at London University in her late 30s.

After college, Boyd became a health journalist, writing about depression, step-parenting and pregnancy. She began writing fiction as a hobby whilst raising three children and working at various day jobs including running a cancer charity, Survive Cancer, working for an engineering company, and an online vitamin site.