Although Clare was their homeland, from a very early date the family had strong associations with Co. Limerick, in particular the area around Kilballyowen. This was acquired by the then head of the family, Hugh O'Grady, in 1309, and has remained the principal seat of the family down to the present day. Unlike so many others of the native aristocracy, the O'Gradys sided with the English in the sixteenth century, and intermarried with a number of powerful English families, thus retaining their influence and possessions through all the vicissitudes of the seventeenth and eighteenth centuries. Two of those marriages, that of Darby O'Grady to Faith, daughter of Sir Thomas Standish of Lancaster in 1633, and of John O'Grady to Mary Elizabeth de Courcy, daughter of Baron Kinsale, are reflected to this day in the personal names in use in the family; the present O'Grady of KIlballyowen, popularly "The O'Grady", and recognised as such by the Chief Herald of Ireland, is Gerald de Courcy O Grady.
The most prominent historical bearers of the name were Standish Hayes O'Grady (1832-1915) and his cousin Standish James O'Grady (1846-1928). Both were deeply involved in the nineteenth-century revival of interest in the the Gaelic past of Ireland, the former as a renowned scholar and student of early Irish history and society, the latter as a popular novelist who based his stories on Irish legends and history.