John Vincent Johnston was living in Cincinnati, Ohio in September 1861 when he joined the Union Navy. He first served on the gunboat the USS St Louis as the First Master. Johnston was on the gunboat which captured Fort Henry on the Tennessee River on February 6th 1862. He was the Union Navy commander in a combined Army – Union expedition on April 1st 1862 to spike the guns of Fort Number 1 located just above the Confederate held Island Number 10 in the Mississippi. For his actions in this expedition Johnston was promoted to Lieutenant. During the bombing of Vicksburg, Mississippi Johnston was in command of the USS Forest Rose, running the Mississippi River. His gunboat stopped as attack by Confederates on February 15th 1864 saving the Union garrison at Waterford, Louisiana. Johnston left the Navy June 23rd 1864.
Johnston died in St Louis, Missouri April 23rd 1912.