Authorities in Toledo said the boy set off the lockdown in early December when he flashed a pellet gun that looked like a real firearm after he was sent to a room for disruptive students.
The boy pleaded guilty last month to inducing panic and two other charges.
The teen was sentenced to do 30 hours of community service and attend counseling.
A prosecutor told The Blade newspaper the boy will not return to the high school and that he likely will be home-schooled.
Toledo’s Scott High School was on lockdown for more than an hour during the standoff.