Phil Sheridan's parents John and Mary Meenagh Sheridan had emigrated from Co Cavan. Sheridan's diminutive stature of five feet five inches earned him the nickname "Little Phil".

In his memoirs, Sheridan writes:

"My parents, John and Mary Sheridan, came to America in 1830, having been induced by the representations of my father's uncle, Thomas Gainor, then living in Albany, NY, to try their fortunes in the New World: They were born and reared in the Co Cavan, where from early manhood my father had tilled a leasehold on the estate of Cherrymoult; and the sale of this leasehold provided him with means to seek a new home across the sea. My parents were blood relations—cousins in the second degree—my mother, whose maiden name was Minor, having descended from a collateral branch of my father's family. Before leaving Ireland they had two children, and on the 6th of March, 1831, the year after their arrival in this country, I was born, in Albany, NY, the third child in a family which eventually increased to six—four boys and two girls."

Perryville was his first engagement as an infantry leader under the command of Major General Don Carlos Buell. While the Confederate troops won a tactical victory, the action forced them to retreat to Tennessee where Sheridan gained major kudos for his performance at the pivotal Battle of Stones River (Murfreesboro).

"The Bold Fenian Men (Down By The Glenside)" sang by Ken Curtis (John Ford's son-in-law) in the 1950 John Ford movie "Rio Grande" starring John Wayne, Maureen O'Hara and J. Carrol Naish as Gen. Philip Sheridan.