Margaret Devlin was born in Mahanoy City, Pennsylvania, United States, on 10 July 1910, to parents Matthew and Marian (née Hoffer) Kane. On 10 February 1933, she married David William Devlin (1907-1992), and the couple would have five children (two sons and three daughters).
She worked as a retail sales clerk, and was a member of the former St. Peter Roman Catholic Church. In her later years, she resided at the Homeland Center retirement community, in Harrisburg, Pennsylvania.
Margaret Devlin died in Harrisburg, Pennsylvania, on 20 August 2020, aged 110 years, 41 days. She was survived by her five children, 18 grandchildren, 37 great-grandchildren, and 23 great-great-grandchildren.
Her age was verified by Fabrizio Villatoro, and validated by LongeviQuest on 6 August 2023.