Henry Wetzel was born on September 14, 1840, in Silver Spring, Pennsylvania, to John Wetzel and Catherine Wise. His father died in the 1840s. He grew up and attended school in North Middleton, Pennsylvania. By the early 1860s, he was living in Ohio. He enlisted in the Union army on August 22, 1862, and he mustered in as a private in Company B of the 121st Ohio Infantry on September 11. The regiment took part in the defense of Cincinnati, the Battle of Perryville, the Battle of Chickamauga, the Siege of Chattanooga, the Atlanta Campaign, the March to the Sea, and the Carolinas Campaign.
Wetzel remained devoted to the Union, writing that he was “fighting for the Union and Constitution as it was and as it ever must be.” During one battle, he reflected, "if I would fall I would fall for my Country, for freedom, and for mankind." He fiercely opposed emancipation, insisting that he was “not fighting for the [n----r].” He later noted that “there is to[o] much [n----r] about this war but still we should stick together for our dear Country, and let the [n----r] go to Halifax.” Nonetheless, in February 1863, he wrote that, “if the freeing of the Negro will crush this rebellion I say free them.” He mustered out on June 8, 1865.
He returned to Pennsylvania after the war, and he married Elizabeth Bucher around 1874. He applied for a federal pension in May 1888 and eventually secured one. By 1910, they were living in Carlisle, Pennsylvania, and Wetzel was working as a painter. His wife died on June 30, 1910. By 1920, he was living with his niece Elizabeth Keller in Mechanicsburg, Pennsylvania. He died there of Bright’s disease on August 14, 1925.