John Brown was born around 1843 in Maine to Samuel and Lucretia Brown. His father was a farmer who owned $700 of real estate by 1850. He grew up and attended school in Hollis, Maine, and his father died in 1853.
He enlisted in the Union army on October 4, 1861, and he mustered in as a private in Company H of the 12th Maine Infantry on November 15. The regiment took part in the siege of Port Hudson. He died of chronic diarrhea in Carrollton, Louisiana, on November 13, 1863.