Because They're Young (1960)

Neil Hendry is the new high school teacher in town, but he is still haunted by a tragic event in his past. However, his friendly, casual style wins the hearts of some of the school's more troubled teens, as well as the principal's secretary. He is able to positively help them both in and out of school. But these same attributes make him an enemy of the principal, who discourages such close relationships between teachers and students.