The modern Irish surnames O'Daly, Daly, Daley, Dayley, Dalley, Daily, Dailey and Dawley are derived from Ó Dálaigh.

Gofraidh Fionn Ó Dálaigh asserted a descent for the family from a 6th-century Dálach, who was the pupil of the saint and poet Colmán the patron of the cathedral town of Cloyne.

[7] The Ó Dálaigh continued to achieve prominence in the societies of their new homelands, becoming poets to various royal courts across Ireland and ruling as minor chiefs over lands outside of Westmeath.

[10] Part of the prestige that attached to the Irish bardic ollamh was derived from fear; a leader satirised in a glam dicenn (satire-poem), by a very able poet, could find his social position badly undermined.

Very talented poets were also believed to possess the power to raise boils on the face of the target of their satires or inflict other bodily harm (early Irish society placed great store on the physical appearance of leaders).

In addition to their poetry, the senior members of the Ó Dálaigh sept were also chieftains, their lands included the minor 'kingdom' of Corca Raidhe (Corcaree) in Meath and Mhuintir Bháire in Cork.

The end of the prominence of the Gaelic-speaking nobility of Ireland, epitomised by the Flight of the Earls, in the early 17th century meant the social eclipse of those bardic families, such as the Ó Dálaigh, that depended on their patronage.

With the loss of land in the wake of rebellions against English rule and in the Plantations of Ireland, most branches of the Ó Dálaigh became, to a greater or lesser extent, impoverished.

[24] Many responded by emigrating and some gained distinction abroad, such as Dionisio (Denis) O'Daly who, following a Jesuit education in France, married into an Irish merchant family in Santa Cruz de La Palma, Canary Islands.

[28] In Ireland, one prominent exception to the trend of impoverishment was the Daly family of Dunsandle, which became part of the Protestant Ascendancy though its members often espoused the extension of Catholic rights.

[29] The Dunsandle Dalys claimed descent from Donnchadh Mór Ó Dálaigh and incorporated the Red Hand of Ulster into their coat of arms to record their ancient Uí Néill connections.