The original Irish for Foley is O Foghladha, from foghlaidh, meaning "pirate" or "marauder". It originated in Co. Waterford, and from there spread to the nearby counties of Cork and Kerry. These are the three locations in which it is still most numerous, though it is now common throughout the southern half of the country. The best known modern Irish bearer of the name, Donal Foley (1922-81), journalist and humorist, came from the original homeland of Co. Waterford. A recent Speaker of the U.S. House of Representatives is Congressman Tom Foley.
In places in Ulster the surname MacSharry (Mac Searraigh), also anglicised as "Sherry", was sometimes mistranslated as "Foley" or "Foaley", because of a mistaken belief that it was derived from searrach, meaning "foal".