At 9 years old, Clem tried unsuccessfully to enlist, was rejected by one company but eventually
taken on by the 22nd Michigan, which allowed him to join as an unofficial drummer boy.

He became a celebrity when the 22nd Michigan was assigned to defend Horseshoe Ridge, but
Confederate soldiers soon surrounded it. A Confederate officer spotted Clem, who was armed
with a musket modified for his size, and demanded that he surrender. Clem shot the officer
and ran, making his way back to Union lines. Though he escaped unharmed, 389 of the 455
men who made up the 22nd Michigan were captured, wounded or killed in the battle.
Johnny Clem was 11 years old.