Mary Kelaher was born and grew up on a property in the Moree district. Both her father and her husband's father were pioneers of the district. She was educated at the Loreto convent at Normanhurst, married at eighteen and had three children, two sons and a daughter.
Kelaher attributed her desire to write to the fact that her father was always reading. She published her first story in The Sydney Mail when she was about twelve and won an award in a short story competition run by a country newspaper. Before her move to Sydney in 1925 she published satirical articles and verse on a fairly regular basis, most of which appeared in The Evening News.
She continued to write after her move to Sydney, although she stated that her domestic occupations meant she was unable to write as much as she would have liked to. She published short stories, serials and poetry in The Australian Woman's Mirrorand also produced several novels. Kelaher described herself as a slow and careful writer who was critical of her own work.