The surname Gilfoyle has its origins in Ireland, particularly from the Gaelic regions where surnames often indicated the family's trade, geography, or ancestry. The name is believed to be derived from the Gaelic Mac Giolla Phoil, which means "son of the follower of Saint Paul." The prefix "Mac" indicates "son of," while "giolla" translates to "follower or devotee," and "Phoil" is a derivation of "Paul." Saint Paul, a prominent figure in Christianity, influenced the naming tradition, signifying a family's religious devotion.

The areas most associated with the origin of the surname Gilfoyle include counties in the western and northern parts of Ireland. Throughout history, the name has also seen numerous variations in spelling, including McGilfoyle, Gilfoy, and Gilfoil, influenced by diverse regional dialects and the anglicization process.

Historical references to the surname Gilfoyle can be found in various medieval manuscripts and land records. One notable early instance is the Annals of the Four Masters, an extensive chronicle of medieval Irish history where the name appears sporadically. You can also find mentions of the name in the Fiants of the Tudor sovereigns, letters patent issued in Ireland.

One of the earliest recorded examples of the surname is found in 16th-century records, with Brian Mac Giolla Phoil mentioned in the annals as a landowner in County Roscommon. Another notable person is Sir Peter Gilfoyle, born in 1643, who played a significant role during the British crown's campaign in Ireland, serving as an advisor in the late 17th century. His writings and correspondence provide valuable insights into the socio-political landscape of the time.

In the 18th century, one prominent Gilfoyle was Eamon Gilfoyle, born 1725, a poet and storyteller who contributed significantly to the preservation of Irish folklore in County Donegal. His works, though largely oral and passed down through generations, were eventually documented by folklorists in the 19th century.

Moving to the 19th century, Bernadette Gilfoyle, born in 1861, was a notable figure in the Irish independence movement. She was an active member of the Ladies' Land League, fighting for tenants' rights and contributing to the cause through her writings and speeches.

Another famous Gilfoyle in more recent history is Sean Gilfoyle, born in 1905, an Irish painter renowned for his depictions of rural Irish life. His works have been exhibited in galleries across Ireland and the United Kingdom, earning him considerable acclaim during his lifetime.

Through these historical figures and records, the surname Gilfoyle has maintained a strong association with Irish heritage, showcasing a blend of religious devotion, social activism, and cultural contributions that have enriched the history of Ireland.