The trial is expected to spotlight alleged systemic violence at Rikers Island, one of the largest jails in America.
Elected Democrats have called for the facility to be shut down, amid a national campaign against police brutality and demands for criminal justice reform.
Expected to last several months, a jury will determine the guilt or innocence of six defendants.
The three other defendants have opted for a bench trial in the case, which is being presided over by Judge Steven Barrett of the Bronx Supreme Court.
A tenth defendant will be tried separately.
The defendants, all former or current officers, face criminal charges including attempted gang assault, falsifying records and official misconduct.
If convicted they could face years in prison.
Attorney Pishoy Yacoub delivered a dramatic opening statement that highlighted the brutality of the beating of Jahmal Lightfoot on the night of July 11, 2012 and the officers’ attempts to cover it up.
The assault was ordered to make an example out of Lightfoot at a time when violence at Rikers Island, New York’s main jail complex, was at an “all-time high,” Yacoub said.
Lightfoot had a criminal record, “but an inmate can be a victim too,” the attorney said in an opening statement to which defense lawyers repeatedly jumped up to object.
Eliseo Perez, an assistant chief of security, and Gerald Vaughn, a captain, ordered that Lightfoot’s teeth be kicked in, said Yacoub, quoting liberally from the swear words and threats he said they used.
Five corrections officers carried out the order, kicking Lightfoot all over his body and “stomping” on his head with the heels of their boots until they fractured both eye sockets and broke his nose, he said.
Officers pinned down his arms and legs, while two others kicked his face “like a football,” Yacoub told the court. At one point, Lightfoot wrapped his hands around his head in self-protection, he said.
A photograph taken after the assault will show that Lightfoot’s face was so swollen his eyes could not be seen, he added.
The officers were supposed to report the incident within 15 minutes, but they waited two hours and only after that made an allegation that Lightfoot had attacked one of them with a sharp object, he said.
He said the officers planted a sharp piece of metal on Lightfoot that was detached from a piece of kit worn by corrections officers, and other inmates heard muffled screams and thumps, he said.
The defendants are all current or former corrections staff. Perez and Vaughn have retired, while the other seven were suspended but have since returned to modified duty, The New York Times has reported.