John McCarty was born around 1831 in Allegheny County, Maryland.  He prepared at the Dickinson Grammar School in Carlisle, Pennsylvania during the 1847-1848 academic school year and then entered the freshman Dickinson College class in the fall of 1848.  During his years at the College, McCarty was a member of the Zeta Psi fraternity as well as the Union Philosophical Society.  He received his bachelor of arts degree in 1852 and thereafter studied law in Cumberland, Maryland.  McCarty relocated to Missouri, where he established a law practice. 

At the outbreak of war, McCarty was commissioned as a lieutenant in the Confederate States Army.  He was killed in action at the battle at Island No. 10 in 1862.