Mathilda was the daughter of Luke White (1740-1824), of county Dublin, Ireland, and his wife Elizabeth de la Maziere (d. 1799), daughter of Peter Maziere of Dublin. Luke became in 1806 high sheriff of county Longford and served as a member of Parliment for Leitrim from 1818 to 1824. Mathilda married in 1826 Hugh Hanon Massy (1793-1886), fourth Baron Massy. Her children succeeded their father as fifth Baron (1827-1874), Hugh Hamon Ingoldsby and sixth Baron, John Thomas William (1835-1915).