But now one of his student accusers has recanted.
The teacher, Aaron Kozlowski wants his reputation restored.
"As always from day one I've maintained my innocence, there's no way this happened, that it's a lie," he said.
And now Kozlowski has the justice system behind him. But it's hard to forget the months upon months of trying to get here.
"I had a bunch of sleepless nights, a lot of stress day in and day out," he adds.
Kozlowski had been a gym teacher and coach at North Shore Middle School in Glen Head for the past 9 years.
Last March several male students told administrators they spotted Kozlowski watching porn on a school computer and committing a lewd act.
"Obviously seeing my mug shot in the newspaper was tough not only on me but on my family," he adds.
Recently one of those students admitted he lied about the entire thing.
The others stopped cooperating with investigators. So the Nassau County District Attorney dropped all criminal charges.
"They recognized that there was no substantiation to any of these charges," said attorney Marc Gann.
Kozlowski has been on administrative leave with pay. The school district says it's still doing its own investigation and is deciding whether to reinstate him.
The Board president telling Eyewitness News:
"Reaching a conclusion is taking longer than any of us would like but we feel strongly that the process will in the end serve the interests of the community."
"I just want to get back to work and have my family and I get back to our normal lives," said Kozlowski.
He says he hopes the boys have learned a lesson.