The surname Kennady originated in Ireland and is a variant spelling of the more common Kennedy name. The roots of the name can be traced back to the 13th century and the ancient Celtic Gaelic language, where it is derived from the words "O'Cinneidigh" meaning "descendant of the ugly-headed one."
The Kennady clan was based primarily in County Tipperary, Ireland, though they also had a strong presence in counties Longford and Westmeath. One of the earliest recorded instances of the name appears in the Annals of Ulster from 1333, referring to Ruaidhri O'Cinneidigh.
In the 16th century, the Kennady name is found in the Fiants of the Tudor Conquest, which were records of royal pardons and land grants issued by the English monarchy during their conquest of Ireland. A notable bearer of the name from this era was Terence O'Kennedy (c. 1500 - c. 1560), a Catholic priest and writer.
The Kennady spelling became more prevalent in the 17th and 18th centuries, with several notable figures emerging from this lineage. One was Mathew Kennedy (1652 - 1735), a member of the Irish Parliament and prominent landowner in County Tipperary.
Another was Patrick Kennedy (1701 - 1779), a Catholic priest and educator who founded the Catholic seminary in Thurles, County Tipperary, which later became St. Patrick's College. He played a significant role in preserving Catholic education in Ireland during the Penal Laws.
In the 19th century, the Kennady name made its way to the United States through Irish immigration. One of the earliest recorded examples is Barnard Kennedy (1785 - 1858), who settled in Philadelphia and became a successful merchant and shipowner.
Finally, a more recent bearer of the Kennady surname was Henry Gratton Kennady (1858 - 1940), a British naval officer and colonial administrator who served as Governor of St. Vincent and the Grenadines in the early 20th century.