The man was being treated at UC Hospital for a leg injury not considered life-threatening. His condition was not immediately known.
Officials said it was not known if the man sustained the injury on school property. He drove to the parking lot to call police, according to Barb Wilson, West Chester spokeswoman.
She said the person reported the injury as a gunshot wound, but officials were not able to confirm that immediately.
Wilson said the man is not a staff member at the school.
There was no immediate threat to the school, Wilson added.
The incident remained under investigation Friday afternoon, she said.