William Green and his half-brother, Samuel Marshall, were born into slavery in Craig County, Virginia. Their mother, Ann Marshall, who had been sold from plantation to plantation, was an early Black migrant to Allegheny County, arriving with her children soon after Emancipation.
Settling in Mansfield (present day Carnegie), the brothers lived and worked together until experiencing a rancorous split after their shoemaking business failed during the Depression that began in 1873. They then went to work as teamsters on different farms.

The rancor continued. A disagreement about how to divide the family’s modest property and its incoming potato crop came to head on September 2, 1875, when Green shot Marshall. He was arrested in Freedom, Pennsylvania, on September 7.
At a trial that produced a transcript not ninety pages in length, Green claimed he acted in self-defense after Marshall assaulted him with a poker. The state argued he acted without provocation in shooting Marshall.
Despite witness testimony of an assault by Marshall and an injury to Green’s head, Green was convicted of first-degree murder on December 16, 1875. He was sentenced to death on July 8, 1876.
Green’s argument that the killing was not properly first-degree was rejected on appeal (Green v. Commonwealth, 83 Pa. 75, 1876). His clemency request was likewise rejected, despite a letter of support from the District Attorney expressing doubt that the killing met the legal standard for first-degree murder.
Lacking the status or the resources to elicit attention or raise the social or legal cost of his execution, William Green was hanged on February 12, 1877. Green was the third Black man to face the death penalty in Pittsburgh and the third to be executed. He was also the first Black capital defendant whose jury could have included a Black man. It did not.
A long and mostly sympathetic newspaper discussion of his case after his execution emphasized his Christian belief and forbearance.