Pleasants was born in Buenos Aires, Argentina, and did not live in the United States until age 13, when he was sent to school in Philadelphia. He worked for the Pennsylvania Railroad and in anthracite coal mines. In 1857, he moved to Pottsville, Pennsylvania, to become a civil engineer in the local mining industry.
Pleasants earned his place in history during the siege of Petersburg, Virginia in 1864 when he masterminded and oversaw a plan to dig a mine shaft from the Union line to the Confederate, fill an underground chamber with gunpowder, and detonate the charge, blowing a large crater in the Confederate lines. The plan was for a follow-up assault to break through the city's defenses by charging into the breach. Though the crater was successfully detonated, the follow-up assault was repulsed, and the Confederate lines held.
Henry Pleasants in The Guns of the South
During the Second American Revolution, Union Lt. Col. Henry Pleasants was captured by the Confederates after the Battle of Bealeton. He was sent to Andersonville and remained a prisoner until an armistice was reached.
On the train trip North with other former POWs, Pleasants elected to stretch his legs while the train stopped in the town of Rocky Mount, Nash County, North Carolina, for refueling. He happened to meet Nate Caudell who was heading South to Nashville after being demobilized from the Army of Northern Virginia. The two struck up a conversation and a friendship over several drinks. This caused Pleasants to miss his train. Caudell convinced him to remain in the Confederacy, and Pleasants obtained employment with the Wilmington and Weldon Railroad.
His employment was terminated in the fall of 1865 for being too soft on the black slaves under his direction. As he told Caudell when he came back north to Nash County, he treated them like men and challenged them to be innovative in their work. They, in turn, started taking pride in their work that they hadn't before, and even began arguing with white men who were less competent. The railroad fired Pleasants not for incompetence, but because he was allowing black men to act as if they were as good as whites, which was unacceptable in the postwar Confederacy.
Upon moving to Nash County, Pleasants decided to buy a farm in the area with his savings and run it with "free" or non-slave labor. This he did successfully, hiring several freeman blacks and several white laborers. A freedman named Israel, skilled as a clerk, came into Pleasants' employ to get away from the disparaging attitudes of his prior employer Raeford Liles.
On March 4, 1868, the Rivington Men turned on the Confederate government and attempted to assassinate President Robert E. Lee. President Lee suspended habeas corpus and put an area under martial law including Nash County (which contained the town of Rivington) and four surrounding counties, under the command of General Nathan Bedford Forrest. As part of this, he recalled Company D of the 47th to service. Although Pleasants had originally served the North, he managed to convince the company commander (Captain George Lewis) and fellow soldiers to allow him to enlist as a private.
When "D" Company faced a seemingly impenetrable defensive position, Pleasants overheard a fellow soldier jokingly suggest going under the Rivington Men's fortified position. This led him to conceive a scheme of building a tunnel and setting off a massive charge of gunpowder under it. Forrest, Pleasants' commanding general, accepted and implemented the plan promoting Pleasants to Lt. Colonel and placing him on his staff to oversee the project. It was successful, breaking the enemy's defenses.
On being informed of Pleasants' promotion in a dispatch, President Lee discovered, in a time-displaced book, Pleasants' averted role in the now-nonexistent Battle of the Crater at Petersburg. Fearing that the Rivington Men would be reminded of this as well, if their spies learned Pleasants was fighting for Lee, and that they would accordingly prepare for an underground attack, Lee censored Pleasants' name from CS Army communiqués.
After the successful completion of the campaign against the Rivington Men, Pleasants resumed farming in Nash County. He was Caudell's best man at his wedding to Mollie Bean. This office he performed in a Confederate colonel's uniform, although he did threaten to cause a scandal by appearing in Federalist blue, which he was also entitled to wear.