The 16-year-old, a sophomore at Orange High School, apparently obtained and used a staffer's password, the Essex County Prosecutor's Office said. He tampered with the records of several students, changing grades and attendance records.
Other students have been disciplined by the school in a suburb outside Newark, and some could face criminal charges, said Chief Assistant Prosecutor Thomas Fennelly.
The teen was arrested Friday and released to the custody of his parents. Officials expect he will be treated as a juvenile.
"Our review continues and the district has taken all appropriate steps pursuant to its policies to provide notice and an opportunity to be heard to the students and parents involved," school officials said in a statement last week. "Furthermore, due to the nature of the actions, the district was legally obligated to report the unauthorized student record changes to the criminal authorities."