Christopher Johnson, 52, of Frankfort, Ind., on Tuesday was charged with possessing a firearm on school property and criminal recklessness for the incident, the Kokomo (Ind.) Tribune reported.
Johnson, a former teacher at the Kokomo Area Career Center, allegedly hid a loaded handgun in a classroom at the center.
Auto tech students discovered the gun while playing with a tape measure, which hit the ceiling, sending the loaded 9mm Beretta and its holster to the floor.
Johnson turned himself in at the Howard County Criminal Justice Center Tuesday morning. He has since posted $7,500 bond and has been released.
Kokomo police notified Kokomo-Center officials that Johnson, who last taught at the school in May 2012, placed the gun in the ceiling.
"I extend special gratitude to the city of Kokomo and its police department for working diligently to bring forth information, solutions, and appropriate actions related to this case," Jeff Hauswauld, superintendent of Kokomo-Center schools, said in a news release.
"It is rather unfortunate that this disconcerting situation was created by the irresponsible acts of one individual. This atypical behavior certainly does not reflect the professionalism displayed daily by the hardworking teachers and staff."