After the United States Supreme Court refused to intervene, those who opposed the executions turned all their attention to Illinois Governor Richard J. Oglesby, who had the power to commute the sentence or even pardon the convicted men. There was no chance that he would do the latter, and Oglesby was said to have confided to a fellow governor a year earlier that he would never exercise executive clemency.

The governor nonetheless patiently received the petitions, read the letters, and carefully considered what to do. Among the appeals was one in behalf of Albert Parsons from his older brother William, who had been a judge in Texas and was now a government official in Virginia. Support for commuting Fielden's sentence came from Judge Joseph Gary, of all people, who praised Fielden's character and idealism, absolved him of prior knowledge of the bomb, and deemed him a "misguided enthusiast." On November 9, the Amnesty Association presented Ogelsby with a petition that contained 41,000 signatures, and he spoke in person with members of the families of Spies, Schwab, Fischer, and Engel. At this point, however, most people believed that he would not intervene.

On Thursday, November 10, Oglesby met with Attorney General Hunt for several hours and consulted with another adviser. Late in the afternoon, with the executions now less than twenty-four hours away, Oglesby finally did commute Samuel Fielden's and Michael Schwab's sentences to life in prison. He entrusted the delivery of the warrant for commutation to his son and private secretary Robert Oglesby, whom he also sent to represent him as a witness to the hangings.

"I am glad it is all over," the governor was quoted as saying. He also stated that he had started to compose a written explanation but then decided against doing so. Captain Black made one last trip that evening to Springfield, arriving before dawn on November 11. He told the governor that he had new evidence, a telegram that claimed that the bomb-thrower had been discovered in New York. Oglesby considered briefly Black's request for a postponement, and then turned it down. The information in the telegram was never verified.

The principles on which Oglesby decided to commute the two men's death sentences seem to have been fairly straightforward. Fielden and Schwab were the only two defendants who asked for mercy (see the "Shadow of the Gallows" section in this Act), they were the least militant of the condemned men, and the evidence against them was the weakest.

Oglesby was born in Kentucky in 1824 and lost his entire family to cholera nine years later. He moved to his uncle's home in Decatur, Illinois, where he worked as a farmer, rope-maker, and carpenter before training for the law in Springfield. He left his practice to serve in the Mexican War, returned briefly to Illinois, joined the California gold rush for a few years, and then came back to Decatur and the law, becoming active in the new Republican Party. After rising to the rank of general in the Civil War, during which he was badly wounded, Oglesby was elected governor in 1864. He was subsequently appointed United States Senator before being reelected governor in 1884.