McKinney apparently lived in Morgan County around the beginning of the Civil War, and helped muster Company H in 1861. He was named first lieutenant of that company. He was also likely involved in the McKinney & Harbison and McKinney & Alexander meat markets, and owned part of the National Hotel for a time.
Around 1869 a company was formed to drill for oil on a farm McKinney owned two miles west of town. They drilled several hundred feet unsuccessfully.
McKinney was the sheriff in the jailhouse when Crook Mershon was lynched.
McKinney was also elected Treasurer of the town. It appeared that he mismanaged or embezzled thousands of dollars during his tenure as Treasurer. He fled to Texas but came back within a few weeks. He was never tried, but rumors of political coverups of the deed were rampant.