John was born in Brooklyn, New York, on the 3rd of February, 1890, and when he was young, he and his family moved to Denver, Colorado, where he attended school and eventually joined the US Army. John graduated from the First Officers Training Camp at Camp Funston in Fort Riley in May of 1917, and was commissioned as a Second Lieutenant. He was deployed to France in support of World War 1 and on the 11th of September, 1918, John wrote one final letter home to his mother. The following day, his actions with the 353rd Infantry regiment of the 89th Division, that earned him the Medal of Honor. The citation reads:

Advancing with his platoon during the St. Mihiel offensive, Second Lieutenant Wickersham was severely wounded in four places by the bursting of a high-explosive shell. Before receiving any aid for himself he dressed the wounds of his orderly, who was wounded at the same time. He then ordered and accompanied the further advance of his platoon, although weakened by the loss of blood. His right hand and arm being disabled by wounds, he continued to fire his revolver with his left hand until, exhausted by loss of blood, he fell and died from his wounds before aid could be administered.

John's Medal of Honor was issued to him on the 22nd of January, 1919, and the previous month, a poem that John had written in that final letter made an appearance in a small Oregon newspaper, the St Helen's Mist, shared to them by John's aunt and uncle. It was titled “Its Patter Touches the Heart” and was later called “Raindrops on Your Old Tin Hat”. It reads:

The mist hangs low and quiet on a ragged line of hills,
  There's a whispering of wind across the flat,
You'd be feeling kind of lonesome if it wasn't for one thing—
  The patter of the raindrops on your old tin hat.

An' you can't help a-figuring—sitting there alone—
  About this war and hero stuff and that,
And you wonder if they haven't sort of got things twisted up,
  While the rain keeps up its patter on your old tin hat.

When you step off with the outfit to do your little bit
  You're simply doing what you're s'posed to do—
And you don't take time to figure what you gain or lose—
  It's the spirit of the game that brings you through.

But back at home she's waiting, writing cheerful little notes,
  And every night she offers up a prayer
And just keeps on a-hoping that her soldier boy is safe—
  The Mother of the boy who's over there.

And, fellows, she's the hero of this great, big ugly war,
  And her prayer is on the wind across the flat,
And don't you reckon maybe it's her tears, and not the rain,
  That's keeping up the patter on your old tin hat?

John Hunter Wickersham was 28 years old when he died near Limey, France, and while he is buried in the Saint Mihiel American Cemetery and Memorial in France (Plot B, Row 19, Grave 12), his family placed a cenotaph for him in the Fairmount Cemetery in Denver, Colorado.