Authorities said John Martin, of Wenonah, had hours of video footage from the cameras and kept a large cache of video screenshots on his cellphone. They said some of the images showed nudity.
Martin, 41, resigned last week as chief custodian at Gloucester Catholic High School in Gloucester City, near Philadelphia, after he was first interviewed by authorities.
The Camden County prosecutor's office said he'd worked there for 18 years and was in charge of the school's video surveillance system.
Martin was charged with invasion of privacy. He turned himself in on Wednesday and was released on his own recognizance on the condition that he not go near the school or any of its students or staff members.
A woman who answered the phone at his home on Wednesday hung up on a reporter.
Police said investigators and school staff are reviewing who's in the videos and are contacting everyone who appeared in them. Most of the images were of girls or women.
The eight pinhole-size cameras were placed in classrooms, in a choir room, backstage in the school auditorium, in maintenance facilities and in an area used by the football team. Some were hidden in ventilation ducts and smoke detectors, and they linked to the school's video security system.
The prosecutor's office has not said who hid them, but it said it was at Martin's direction.
Authorities said they are still probing who else saw the footage. They say Martin showed images to at least two other people but there's no evidence he posted them online or sold them.
Principal John Colman, in a letter to parents that was posted on the school's website, said the school was cooperating with authorities.
"It is our conviction and our commitment that the security and well-being of our students -- your sons and daughters -- is our first and most important obligation," he wrote.
He said he would keep parents apprised of developments in the case, but he asked that they be patient because some details could be withheld to avoid compromising the investigation.