On July 7, 1865, at 1:15 P.M.,a procession led by General Hartranft escorted the four condemned prisoners through the courtyard and up the steps to the gallows. Each prisoner's ankles and wrists were bound by manacles. Mary Surratt led the way, wearing a black bombazine dress, black bonnet, and black veil. More than 1,000 people—including government officials, members of the U.S. armed forces, friends and family of the accused, official witnesses, and reporters—watched. General Hancock limited attendance to those who had a ticket, and only those who had a good reason to be present were given a ticket. (Most of those present were military officers and soldiers, as fewer than 200 tickets had been printed.) Alexander Gardner, who had photographed the body of Booth and taken portraits of several of the male conspirators while they were imprisoned aboard naval ships, photographed the execution for the government. Hartranft read the order for their execution. Surratt, either weak from her illness or swooning in fear (perhaps both), had to be supported by two soldiers and her priests. The condemned were seated in chairs, Surratt almost collapsing into hers. She was seated to the right of the others, the traditional "seat of honor" in an execution.
White cloth was used to bind their arms to their sides, and their ankles and thighs together. The cloths around Surratt's legs were tied around her dress below the knees. Each person was ministered to by a member of the clergy. From the scaffold, Powell said, "Mrs. Surratt is innocent. She doesn't deserve to die with the rest of us". Fathers Jacob and Wiget prayed over Mary Surratt, and held a crucifix to her lips. About 16 minutes elapsed from the time the prisoners entered the courtyard until they were ready for execution.
A white bag was placed over the head of each prisoner after the noose was put in place. Surratt's bonnet was removed, and the noose put around her neck by a Secret Service officer. She complained that the bindings about her arms hurt, and the officer preparing said, "Well, it won't hurt long." Finally, the prisoners were asked to stand and move forward a few feet to the nooses. The chairs were removed. Mary Surratt's last words, spoken to a guard as he moved her forward to the drop, were "Please don't let me fall.
Surratt and the others stood on the drop for about 10 seconds, and then Captain Rath clapped his hands. Four soldiers of Company F of the 14th Veteran Reserves knocked out the supports holding the drops in place, and the condemned fell. Surratt, who had moved forward enough to barely step onto the drop, lurched forward partway down the drop—her body snapping tight at the end of the rope, swinging back and forth. Surratt's death appeared to be the easiest. Atzerodt's stomach heaved once and his legs quivered, and then he was still. Herold and Powell struggled for nearly five minutes, strangling to death.