Born in Abergavenny, Monmouthshire in 1876, White started writing as a child, contributing essays and poems to children's papers. Later she began to write short stories, but it was some years before she wrote books.

She left employment in a government job working for the Ministry of Pensions in order to pursue writing. Her writing was to make her one of the best known crime writers in Britain and the USA during 1930s and 1940s.

Her first three works, published between 1927 and 1930, were mainstream novels. Her first crime novel, published in 1931, was Put Out the Light.

She died in London in 1944 aged 68. Her works have enjoyed a revival in recent years with a stage adaptation of The Lady Vanishes touring the UK in 2001 and the BBC broadcast of an abridged version on BBC Radio 4.