Dervla McTiernan was born in County Cork, Ireland to a family of seven. She studied corporate law at the National University of Ireland, Galway and the Law Society of Ireland, and practiced as a lawyer for 12 years.  Following the global financial crisis she moved with her family to Western Australia, where she now works for the Mental Health Commission.

In 2015 she submitted a story for the Sisters in Crime Scarlet Stiletto competition and was shortlisted. This gave her the confidence to complete the novel that would become The Rúin.