John Allen Shepherd was born on December 30, 1835, in DeRuyter, New York, to Allen and Lydia Shepherd. His father was a shoemaker who owned $1,000 of real estate and $300 of personal property by 1860. He grew up and attended school in DeRuyter, and by 1860, he was working as a blacksmith.
He enlisted in the Union army on November 2, 1861, and he mustered in as a private in Company D of the 10th New York Cavalry on November 19. The regiment took part in the Battle of Fredericksburg, the Battle of Gettysburg, the Overland Campaign, and the siege of Petersburg. He was reportedly “injured by fall of horse” near Aldie, Virginia. He mustered out on November 26, 1864.
He settled in Truxton, New York, after the war, and he earned a living as a blacksmith. He married Sabria J. Spargur, and they had at least three children. He applied for a federal pension in November 1879 and eventually secured one. He died in Truxton on January 10, 1906.