Two people were shot, a 13-year-old girl and a teacher.
Jowitt said the situation was "resolved extremely quickly", and the student was taken into custody.
Parents can pick up high school and the West middle school students when the threat is cleared, Noblesville Schools said in the email.
Jowitt said a second threat that locked down Noblesville High School is not believed to be related to this incident. According to a bio page on the school's website, he was an elementary education major.
When asked to elaborate on his praise about the response, Indiana State Police Superintendent Doug Carter said: "Wait 'til one day we can tell you that story".
A statement from the Indiana State Teachers Association said thoughts and prayers aren't enough to keep students and educators safe. According to Noblesville police, a teacher and a student were taken to a hospital with injuries. Investigators also said they do not know yet if the shooter had any previous problems at school or run-ins with police.
This is now the 23rd school shooting to happen in 2018, where innocent students and faculty were either injured or killed as a result.More news: Europe, US 'far from a compromise' on Iran nuclear deal: Germany
"Please pray for my son Jason".
"Our thoughts are will all those affected by this disgusting situation", he tweeted.
Noblesville is north of Indianapolis.
Gov. Eric J. Holcomb, who was returning to Indianapolis from a trip to Europe, said in a statement that he was monitoring the situation and that about 100 Indiana State Police officers were made available to work with local authorities.
Vice President Mike Pence, the former governor of IN, tweeted about the incident. She also noted specifically where he was shot: once through the abdomen, once in the hip, and once in the forearm.
Aerial footage shows a shocking and chaotic scene, with students evacuating the building with their hands raised and panicked parents desperately searching for their children.