Her paternal grandfather was William Smith O'Brien, and a maternal cousin was Mary Spring Rice.
Following the death of her mother from tuberculosis, the three siblings were raised by their aunt, Charlotte Grace O'Brien.
[1][2][3] In 1894, she married a childhood friend of her brother, barrister and administrator Arthur Beresford Cane, CBE (died 1939).
O'Brien joined the Voluntary Aid Detachment of the British Red Cross, serving at the headquarters from 1914 to 1917 under Katharine Furse.
She eventually moved to England and became the VAD assistant director, and retired in 1919 with a CBE.