After the death of her father, her mother owned and managed a store in Ballaghaderreen, Monica Duff & Co Ltd. She was educated with her brother by his tutor, where Deane excelled at mathematics.
[3] When Andrew Kettle visited he noted that she was "remarkable woman who seemed to be quite at home at the head of a business that looked like the centre not of a town like Ballaghaderreen, but a province."
When Agnes Bernard of the Sisters of Charity moved to Ballaghaderreen, Deane was a prominent benefactor, donating large sums as well as sometimes paying for meals to be delivered to them.
[1] Deane had no children of her own, but she was involved in the raising of the young family of her uncle John Blake and his wife Adelaide following their deaths in 1866 and 1872 respectively.
She was chosen as honorary president, but owing to her business taking up the majority of her time, Anna Catherine Parnell was viewed at the real leader of the group.