A visibly relieved Cruz declined to comment. His lawyer, Christian J. Hoey, described the verdict as "a good decision."
"Nobody celebrates the fact someone was injured," he said. "But he's a heck of a law enforcement officer and an asset to the United States."
Cruz, 44, of Oxford, never denied that he caused the injuries sustained by 22-year-old Zachary Bare during an August raid on the man's home in Chester County. He testified Friday that he did not realize Bare was handcuffed at the time and thought he was trying to stand to attack him.
He told jurors that he pinned Bare's shoulder with his foot in an attempt to keep him on the ground - all while Bare was screaming obscenities and rolling on the floor.
"I responded the way I was trained to respond," he testified Friday. "I reacted to what I saw. If I fail, I don't come home to my family."
Prosecutors described a vastly different incident - involving a kick to the back of Bare's head, witnessed by at least one police officer, as the man lay handcuffed and prone on his kitchen floor.
The impact left Bare with shattered teeth, a broken nose, and two facial fractures.
Cruz was working as a liaison to a Chester County drug task force and assisting the West Whiteland Police Department on what was to be a surprise assault on a suspected meth lab in an Exton house. When officers arrived, the men inside spotted them and tried to escape.
Officer Jeffrey McCloskey told jurors last week he saw Bare running nearby and followed him to a house five doors down. He ordered Bare to the floor as another officer handcuffed him. Another West Whiteland officer, Glenn Cockerham, testified he witnessed Cruz kick Bare - a use of force he later described in an investigative report as "totally unnecessary."
Investigators eventually determined that Bare was not at the drug house at the time of the raid and he was never charged in the case.
Hoey contended throughout the six-day trial that the West Whiteland officers sought to shift blame for Bare's botched arrest onto Cruz.
"We're obviously disappointed," Linwood C. Wright Jr., one of the assistant U.S. attorneys who tried the case, said Monday. "We believe in the West Whiteland Police Department."
Monday's verdict came three years after a Chester County grand jury declined to indict Cruz over the same incident and two years after the Pennsylvania State Police settled a lawsuit from Bare for $125,000.
Cruz was suspended without pay shortly after a federal grand jury indicted him in August 2013. He is expected to return to his job as a corporal in the state police's Avondale barracks, Hoey said.