John was born on the 4th of October, 1896 in Fayetteville, Arkansas, to George and Melissa and grew up with two sisters and one brother. He enlisted in the US Marine Corps in May of 1917 and was deployed to France with the 6th Marine Regiment and he participated in the Battles of Belleau Wood, Chateau-Thierry, and Blanc Mont Ridge. He had earned a Silver Star for helping capture an enemy machine gun on the 15th of September, another Silver Star for his actions between the 1st and 10th of October, and a third Silver Star for the same time period. It was his actions on the 3rd of October, the day before his 22nd birthday, that would earn him both the Army and Navy Medals of Honor. The citations read:

Army

Pruitt single-handedly attacked two machineguns, capturing them and killing two of the enemy. He then captured 40 prisoners in a dugout nearby. This gallant Marine was killed soon afterward by shellfire while he was sniping at the enemy.

Navy

For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty in action with the enemy at Blanc Mont Ridge, France, October 3, 1918. Corporal Pruitt single-handed attacked two machine-guns, capturing them and killing two of the enemy. He then captured 40 prisoners in a dugout nearby. This gallant soldier was killed soon afterward by shell-fire while he was sniping the enemy.

John was killed in action shortly after, on the 4th of October, 1918, his 22nd birthday. He was originally buried in France but his remains were later returned to the US and John Henry Pruitt is now buried in Arlington National Cemetery: Section 18, Lot 2453.