John Freeman Mackie was born on 1 October 1835 in New York City. Working there as a silversmith, he enlisted in the U.S. Marine Corps at the Brooklyn Navy Yard on 24 April 1861. His first assignment was on the USS Savannah as part of the shipâ€™s Marine Detachment. On 1 March 1862, Mackie was promoted to the rank of corporal and was assigned to the ironclad U.S.S. Galena under the command of Commander John Rodgers.
On 15 May 1862, a small Union navy flotilla which included the Galena, Aroostook, Port Royal, Naugatuck and the famous USS Monitor attacked Confederate Fort Darling, located about 4 miles below Richmond, Virginia, near a bend in the James River called Drewryâ€™s Bluff. Fort Darling, sited on top of the bluff, guarded the river entrance to the Confederate capital and was of tremendous strategic importance to the rebel cause. At 0600 Galena opened fire on the well-defended fort, but this attack was strongly resisted by the Confederates. Almost immediately Commander Rodgers was severely wounded by a Confederate shell. Early on in the fighting it was obvious that the Union ships were at a clear disadvantage. The well-armored USS Monitor was unable to elevate its guns to properly target the fort and a hundred pound gun on the Naugatuck exploded and forced that ship to also retire out of range. The Port Royal and Aroostook were both wooden hulls and not able to withstand the plunging fire from the fort. Thus the lone remaining ironclad, Galena, was forced to fight alone for over four hours.
While the Galena was indeed considered an ironclad ship, its armor was still fairly thin as compared to that of the more powerful USS Monitor. Confederate rounds from the fort repeatedly penetrated Galenaâ€™s armor plating and caused a significant number of casualties. To make matters worse, Confederate Marines manning rifle pits on the nearby riverbank used sharpshooters to pick off any exposed personnel. At the height of the fighting, a 10-inch round once again penetrated Galenaâ€™s armor belt and smashed into one of its 100 pound Parrot guns, killing nearly its entire crew. Shouting, â€ścome on boys, hereâ€™s a chance for the Marines,â€ť Mackie and a number of nearby comrades quickly manned the Parrot rifle and kept the weapon in action.
By noon, the Galena was entirely out of ammunition and Commander Rodgers moved the vessel down river and safely out of range. During the intense fighting in front of Fort Darling, the Galena had been hit dozens of times by solid shot. Twelve sailors and one Marine had been killed and eleven more men were wounded.
For his conspicuous performance in combat at the battle of Drewryâ€™s Bluff, Mackie was promoted to sergeant and recommended for the Medal of Honor. Reassigned to the USS Seminole, Mackie received the medal on 10 July 1863 while anchored off Sabine Pass in Texas. He was honorably discharged from the Marine Corps on 23 August 1865 in Boston, Massachusetts after having served over 4 years of continuous service. During his time on active duty, Mackie had participated in sixteen major naval engagements and was in dozens of skirmishes in his role as a Marine assigned to Union navy ships. The only wartime injury he received occurred in January 1864 when he was struck in the head with a chain hook while trying to quell a group of rioting Seminole sailors. Mackie was the first U.S. Marine to receive the Medal of Honor.