On April 10, 1861, Brigadier General P.G.T. Beauregard, commander of all Confederate forces at Charleston, South Carolina, received new orders from Secretary of War LeRoy Pope Walker in the Confederate capital of Montgomery, Alabama. A Federal naval expedition was en route to Fort Sumter in Charleston Harbor, and within days would bring much it needed food and other supplies. Beauregard’s orders were to demand the fort be evacuated immediately. If refused, Beauregard was to "…proceed in such manner as you may determine…to reduce it." This news sent Charleston into an excited, frenzied state of anticipation. Diarist Mary Chesnut wrote of "the merriest, maddest dinner we have had yet." Charleston’s men were "more audaciously wise and witty" than ever.

Before noon on April 11th, General Beauregard ordered Colonels James Chesnut and James A. Chisholm, plus Captain Stephen Dill Lee, to present a surrender ultimatum to Fort Sumter’s commander, U.S. Major Robert Anderson. Anderson had been Beauregard’s artillery instructor at West Point. Now Beauregard had the upper hand, with Anderson heavily outgunned. Yet Anderson rejected Beauregard’s ultimatum, adding that his garrison would be "starved out in a few days." Chesnut reported this to Beauregard, who sent the party back to Fort Sumter with a final ultimatum after midnight on April 12th. With the Federal naval expedition just outside Charleston Harbor, Anderson gave an ambiguous reply that he would evacuate on April 15th, but only if not threatened, fired upon, ordered to stay or resupplied. Chesnut handed him a personal handwritten note, "We have the honor to notify you that [Beauregard] will open fire of his batteries on Fort Sumter in one hour." It was 3:20 AM.

At 4:30 AM on April 12, 1861, Confederate Lieutenant Henry S. Farley’s 10-inch mortar at Fort Johnson on James Island fired a signal shot, arcing high above Fort Sumter about 2400 yards away. Quickly, some 42 other guns opened fire on Fort Sumter from James, Morris and Sullivan Islands. Charleston’s citizens raced to rooftops to watch the bombardment, to pray, or to shout after every explosion. Mary Chesnut later wrote in her diary, "I sprang out of bed, and on my knees prostrate, I prayed as I never prayed before." Fort Sumter withheld its limited defense until 7:00 AM when Captain Abner Doubleday fired their first response, barely missing its target on Morris Island.

Throughout the 12th into the 13th a steady albeit largely inaccurate Confederate bombardment was answered by a limited Federal response. Confederate gunners cheered in tribute each time a rare Federal shot was fired. Fort Sumter’s flag was eventually shot away, prompting Louis Wigfall, a former U.S. Senator from Texas, to assume Major Anderson intended to surrender. Without authorization, Wigfall rowed out to the fort. With fires threatening to explode Fort Sumter’s main powder magazine, Wigfall convinced Anderson to surrender at about 1:30 PM. When General Beauregard’s authorized emissaries arrived a short time later, led by Captain Lee, Anderson was furious at having "surrendered" to the wrong man. Lee persuaded Anderson against resuming the fight, and formal surrender terms were agreed upon. Despite some 3,341 shells having been fired at Fort Sumter, no one was killed or seriously wounded on either side. Other than the accidental deaths of two Federal gunners during a ceremonial surrender cannonade on April 14th, the bombardment of Fort Sumter was a near bloodless start to the bloodiest war in America’s history.