Anglicized form of Irish Ó Ceallaigh, meaning 'descendant of Ceallach' (bright-headed or warrior).
Kelley is one of many spelling variations of the storied Irish name Kelly, derived from the Gaelic clan name Ó Ceallaigh, meaning "descendant of Ceallach." The personal name Ceallach is ancient and contested in its precise meaning; scholars have proposed interpretations ranging from "bright-headed" to "war" or "contention," though the most widely accepted reading points to something like "strife" or "bright warrior." Whatever its exact root, the name was borne by several early Irish saints and kings, cementing its prestige in the Gaelic world.
The Ó Ceallaigh sept was one of the most powerful in Connacht, and their influence spread the name far beyond its provincial origins. With the great waves of Irish emigration to America, Australia, and Britain in the nineteenth century, Kelly and its variants became among the most common Irish-origin surnames in the English-speaking world. Their crossover into given-name use followed naturally—by the mid-twentieth century Kelly had firmly established itself as a first name, used for both boys and girls, with Kelley representing the feminine-leaning spelling favored particularly in the United States.
The actress and later Princess of Monaco Grace Kelly gave the name an elegance it had not previously enjoyed in popular imagination. Kelley with its double-l has a slightly softer, more personal feel than the clan-name spelling, and it has been a steady choice for American parents since the 1960s, carrying a blend of Irish heritage and mid-century American ease.