John Mackie was born on October 1, 1836, in Manhattan, New York. He worked as a silversmith before enlisting in the U.S. Marine Corps on April 24, 1861, at the Brooklyn Navy Yard. Mackie served aboard the frigate USS Savannah from April 1861 to February 1862, and then as Corporal of the Marine Guard aboard the broadside ironclad USS Galena from April 1 to November 10, 1862. During his time aboard USS Galena, Cpl Mackie participated in the Battle of Drewry's Bluff on May 15, 1862, and he was later awarded the first Medal of Honor ever awarded to a Marine for this action on July 10, 1863. He was advanced to the rank of Sergeant on November 1, 1862, and he served at the Norfolk Navy Yard in Norfolk, Virginia, from November 1862 to June 1863. His next assignment was as Orderly Sergeant in Charge of the Marine Guard aboard the steam sloop USS Seminole from June 1863 to August 1865, and during this time he participated in the Battle of Mobile Bay in August 1864. Orderly Sergeant Mackie was honorably discharged from the Marine Corps at the Boston Navy Yard on August 23, 1865. He died on June 18, 1910, and was buried in Arlington Cemetery in Drexel Hill, Pennsylvania.

His Medal of Honor Citation reads:

While serving on board the U.S.S. GALENA, in the attack on Fort Darling, at Drurys Bluff, James River, May 15, 1862; particularly mentioned for his gallant conduct and services and single acts of devotion to duty.