Sr. Mary Ellen was born Johanna Cunningham in 1895 in Kilbaha, Newtownsandes (now Moyvane), Co. Kerry to Richard Cunningham and Brigid Dore. She was a granddaughter of Bryan Cunningham and Johanna Hudson.
At the age of 20 she and her younger sister Margaret travelled to Concordia, Kansas - where a distant relative, John Francis Cunningham, was a bishop - to enter the convent of the Sisters of St. Joseph. Johanna and Margaret were just two of many Cunningham and Mulvihill relatives that Bishop Cunningham encouraged to enter religious life in Kansas.
Sr. Mary Ellen worked as a nurse in El Paso, Texas for some time before returning to Concordia to work in St. Anthony's Hospital. She died in Concordia in 1989 aged 93.