She was a farmer's daughter from Northern Ireland.
She was AMW's servant intermittently for some fifteen years (1840-late 1850s). They probably met at Springfield, MA, where Brennan later settled; Brennan's brother James was also living there. By 1862 she was married to a Mr Bergen and resided at New Haven, CT. The Whistlers gave to Brennan a portrait of JW at the age of ten years old, painted in St Petersburg by C. A. F. Fiefster. The picture later descended to Brennan's niece Mrs John J. Barrett, and eventually to the Connecticut Valley Historical Society.