The alleged attacker, a 37-year-old staff member, is accused of assaulting Keysborough Secondary College principal Aaron Sykes on school grounds about 3pm on Tuesday.
Police arrived at the school, in Melbourne's outer southeast, within nine minutes of receiving the call for assistance.
The staff member was arrested at the school, with both men taken to hospital with non-life-threatening injuries.
Education Minister Ben Carroll on Wednesday morning confirmed Mr Sykes had been discharged from hospital and is recovering at home.
He said the school had reopened, with student support officers on site to offer assistance to staff and students.
"My thoughts are with the school principal, his family and his friends that will all be suffering from what occurred with this very traumatic incident," Mr Carroll told reporters.
"The school took all the appropriate measures, the staff acted promptly, and there's now an investigation under way. I'm just so grateful that the principal is at home and recovering."
Mr Carroll confirmed the alleged assault was carried out by a staff member and said no students witnessed the incident.
Police have since charged the 37-year-old man with multiple offences including unlawful assault, intentionally causing injury and recklessly engage in conduct placing a person in danger of serious injury.
He has since been released from hospital after suffering a minor injury.
The man will appear before Dandenong Magistrates' Court on Wednesday.
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