Shields Green was born into slavery in South Carolina, where he was called Emperor. He escaped from slavery a little over a year before the events at Harper's Ferry, fleeing from Charleston, South Carolina, and making his way north to freedom in Rochester, New York. It is thought that he left behind a son in slavery in South Carolina. Other reports also have Green working as a sailor before he joined up with Douglass in Rochester.
Green first met John Brown at the house of the abolitionist Frederick Douglass in Rochester. Later Green accompanied Douglass to Chambersburg, Pennsylvania, to meet Brown for discussions about his plans. Green and Douglass met with Brown and John Henry Kagi at an abandoned stone quarry near Chambersburg. Douglass left after disagreeing with Brown on planning an armed attack on a Federal arsenal, but Green stayed to join the raiders.
Years later Douglass described Green in his memoir:
"Shields Green was not one to shrink from hardships or dangers. He was a man of few words, and his speech was singularly broken; but his courage and self-respect made him quite a dignified character."
During the raid, Green and others were assigned to recruit slaves from the nearby countryside to join the fighting. Green was with Dangerfield Newby and O.P. Anderson at the Arsenal during the raid, where he is said to have immediately avenged Newby's death. According to Douglass, Jeremiah Anderson, one of Brown's men who escaped capture, said that Green could have escaped with him. "I told him to come; that we could do nothing more, but he simply said he must go down to de ole man." (There is some dispute as to Douglass' source, as later in 1870, he attributed the same statement to O.P. Anderson, who seems a more likely source)
Green and Copeland were indicted, tried, and convicted with John Brown for treason against Virginia and other crimes, but did not say a word during the trial. On the morning of John Brown's execution, Green sent word to Brown that he was glad to have fought with him and awaited his own execution willingly.
Green and Copeland were hanged two weeks after Brown. After the execution, the cadavers of Green and Copeland were exhumed and taken to Virginia to the Winchester Medical College, for dissection by students in the anatomy laboratory. Professor James Monroe of Oberlin College, a family friend of Copeland from Oberlin, Ohio, searched for Copeland's body, but found Green's, and was unable to retrieve either body. "We visited the dissecting rooms. The body of Copeland was not there, but I was startled to find the body of another Oberlin neighbor whom I had often met upon our streets, a colored man named Shields Greene." Likewise the body of Watson Brown was also "claimed" by Winchester Medical College as a teaching cadaver for students. The College was later burned to the ground by Union troops in the Civil War. Watson Brown was reburied beside his father in 1882.On December 25, 1859, a memorial service was held in Oberlin for Copeland, Green, and Lewis Sheridan Leary, who died during the raid.
A cenotaph was erected in 1865 in Westwood Cemetery to honor the three "citizens of Oberlin." The monument was moved in 1971 to Martin Luther King, Jr. Park on Vine Street in Oberlin. The inscription reads:
"These colored citizens of Oberlin, the heroic associates of the immortal John Brown, gave their lives for the slave. Et nunc servitudo etiam mortua est, laus deo
[And thus slavery is finally dead, thanks be to God].
S. Green died at Charleston, Va., Dec. 16, 1859, age 23 years.
J. A. Copeland died at Charleston, Va., Dec. 16, 1859, age 25 years.
L. S. Leary died at Harper's Ferry, Va., Oct 20, 1859, age 24 years."