The videotaping allegedly happened in the men's locker room at Six Flags Great America amusement park in Gurnee.
Jaime Jimenez, 39, is charged with two felonies, including unauthorized video recording.
Jennifer Dugan of Six Flags Great America said on Saturday that an off-duty police officer witnessed what appeared to be inappropriate behavior at Hurricane Harbor and notified park security.
Security personnel immediately responded and detained the individual. He was arrested by the Gurnee Police Department.
"Apparently, Mr. Jimenez was using his iPhone in the men's locker room at Hurricane Harbor and secretly video-recording people in the stalls next to him while he was in there," said Gurnee Police Commander Jay Patrick. "In this instance, one of the victims was an off- duty police officer from the Lake County area, and he confronted him and chased him down... he was arrested."
Patrick said investigators found video footage of men on Jimenez's phone.
"There were clearly male adults, but there were also some clearly juvenile subjects," said Patrick. "Some were showering, some were using the bathroom, some were just getting dressed... He was charged with one count of unlawful videorecording."
Patrick said Jimenez is cooperating with police.
"Based on his information that he was giving us, this wasn't his first time he had done something like this, so we felt there may be other evidence back at his apartment in Chicago, so we contacted the Chicago Police Department," said Patrick.
Patrick said some electronic devices, including computers, were removed from the home and brought to the police station for further analysis.
Jimenez lives in the 2200-block of S. Canal in Chicago. He is a fifth grade elementary school teacher at the Robert Healy elementary school.
Chicago Public Schools spokesperson Monique Bond said in a statement that the schools are aware of his arrest and charges and have started an internal investigation.
"He does not have access to the classroom and will not have access to the computer either," said Patrick.
Patrick said the investigation is continuing and there may be additional charges.
Gurnee police are working with Chicago Police, Chicago Public Schools, the Lake County State's Attorney and the Cook County State's Attorney.
Patrick said authorities will be examining all computers at Robert Healy Elementary School that Jimenez had access to.