Irish and Scottish: Anglicized form of Gaelic Ó Ceannéidigh ‘descendant of Ceannéidigh’ (from ceann ‘head’ + éidigh ‘ugly’); or from the Scottish Gaelic Mac Cinnèidigh, consisting of mac ‘son’ with an equivalent name. Compare Canaday , Cannady , Cannedy , Kannady , and Kenedy .History: Kennedy ancestral lands are found both in Ireland and in Scotland, where the family's medieval ancestral seat is sited on the Ayrshire coast, facing the Irish Sea. — The great-grandparents of President John Fitzgerald Kennedy (1917–63) came to North America as immigrants from Ireland in the 1840s. His paternal great-grandparents were Patrick Kennedy (1823–58), born in Dunganstown, County Wexford, Ireland, and Bridget Murphy, who was born probably in Owenduff, County Wexford, Ireland c. 1827; they came to Boston, MA, in 1849. His maternal great-grandparents were Thomas Fitzgerald (1823–85), who was born in Bruff, County Limerick, Ireland, and Rose Anna Cox, who was born probably in Tomregan or Kinawley, County Cavan, Ireland, c. 1835; they came to Boston, MA, in 1857. — An early Scottish Kennedy forebear of a quite different family was British colonial official Archibald Kennedy (1685–1763), the son of Alexander Kennedy of Craigoch, who emigrated to NY c. 1710.
Dictionary of American Family Names © Patrick Hanks 2003, 2006.