John MacKenzie was born in Bridgeport, Connecticut, on 7 July 1886; he enlisted in the Navy on 20 December 1902 when he was just 16 years old. He was discharged five years later, but returned in 1917 when the United States entered World War I.

MacKenzie was assigned to USS REMLIK (SP-157), a steam-powered yacht the Navy purchased from a private owner for use as a patrol vessel. MacKenzie’s Medal of Honor citation reveals his actions on 17 December 1917, when REMLIK was caught in a storm in the Bay of Biscay:

“During this gale, there was a heavy sea running. The depth-charge box on the taff-rail aft, containing a Sperry depth charge, was wash[ed] overboard, the depth charge itself falling inboard and remaining on deck. MacKenzie, on his own initiative, went aft and sat down on the depth charge, as it was impracticable to carry it to safety until the ship was headed into the sea. In acting as he did, MacKenzie exposed his life and prevented a serious accident to the ship and probable loss of the ship and the entire crew.”

When the war ended, MacKenzie was once again discharged into civilian life. He opened a restaurant and lived quietly until his death in Massachusetts on 26 December 1933 at the age of 47. A baseball field in his adopted hometown of Holyoke was named MacKenzie Stadium in his honor; a plaque under the American flag in left field details his act of heroism.