John Wesley Clement was born on July 1, 1826, in Charlestown, Massachusetts, to John Clement and Lucy Symmes. His father was a soap chandler. They eventually moved to Exeter, New Hampshire, and he attended Phillips Exeter Academy. He travelled to California in 1849 in search of gold, but he returned home without success. By 1860, Clement was working as a clerk in Exeter, and he owned $400 of personal property.
He enlisted in the Union army on July 29, 1861, and he mustered in as a corporal in Company B of the 3rd New Hampshire Infantry on August 22. According to his service records, he was 5 feet, 10 inches tall, with light hair and hazel eyes. The regiment took part in the Battle of Fort Wagner and the siege of Petersburg. He was reduced to the ranks on September 24, 1861, but he was promoted to corporal again on December 5, 1862.
In September 1862, he declared his opposition to Black enlistment. He wrote that "I don't think they would ever make good soldiers, for the reason that they have been used to obeying white men so long that if they should happen to get taken prisoners the Rebs could make them turn right round and fight as hard against us as they ever would for us." The following month, he argued that "patriotism...soon gets played out in the Army, that is after a man has been in the Army a while he just does what he has to do and no more."
He supported conscription. In May 1863, he declared that "it is the only right way to raise an Army...if men were drafted the Army could be filled up in the shortest possible time without the farce and humbug of big bounties and all that sort of trash such as we saw last summer and which I consider more disgraceful to the country than twenty drafts could be." He refused to reenlist in 1864, writing that “Unpatriotic or not I think I have done about my share without going in for 3 yrs more.” He mustered out on August 23, 1864.
He returned to Exeter after leaving the army, and he resumed his work as a clerk in a grocery store. He married Ann Fellows on April 18, 1872. They had no children, but Clement helped raise Ann’s two children from a previous marriage. He remained in Exeter for the rest of his life, and he died there of “exhaustion” on December 23, 1900.