McKinley was the son of an Irish immigrant father who married a Gainesville belle. Both his parents died in his youth and he and his three siblings were raised by a guardian. In 1861 McKinley enlisted with Company E of the 18th Mississippi Regiment, Barksdale's Brigade. He served through the Civil War and was captured in 1864 and held at Point Lookout, Maryland for six months.
After the war McKinley briefly resumed his schooling before moving to his brother's farm. He married the former Virenda Priscilla Poythress of Virginia in 1869. He and his family relocated to East Lake in 1890 where he was appointed postmaster. He later was elected Mayor of that city in the years before it was annexed into Birmingham.
- "Robert N. McKinley, Mayor On East Lake" [sic] (July 1, 1903) The Birmingham News, p. 36
- Robert Neal McKinley at Findagrave.com