The Private War of Major Benson (1955), directed by Jerry Hopper.
As punishment for opening his big mouth to reporters, a hard-as-nails officer is assigned to a year running ROTC at a Catholic boys school. He also has to coach football and secretly buys a beginners handbook. The school doctor is nice looking, so it may not be a complete waste. He terrorizes the students, but would you believe: everyone learns from each other?
Not a great film, but family-oriented and a rare Charlton Heston comedy. He uses his intense bigger-than-life persona to good comic effect. Some wit, lots of sugar. With Julie Adams, but -- alas -- she has no Amazonian swimsuit:
I mean, she wears normal clothing.
I remember bits of this from when I was a kid and it just became available on DVD. The source quality is just fair.
The school is a real place: St. Catherine's Academy, and the students appear as extras.
With David Janssen (age 24) and Sal Mineo (age 16, murdered at age 37).
The Universal Vault Series DVD-R has a 1.33 aspect ratio. The IMDB and other references say it should be 2.0:1 ("Superscope"?). I believe this edition must be presented open matte, because the composition has plenty of room at the top and bottom; an enormous amount of head room in some scenes.