The Lieutenant (1963)

Stew Sallaway, champion goldbrick at Clary High, could always depend on his buddy Bill Rice to get him out of a jam. Now Stew is a Marine private, and his ailing father asks Rice to have the boy to his platoon.

Rice is pressed upon by a friend to look after his girl in advance of a year-long posting in the far east without leave. She demands they marry right away, and it falls on Rice to quickly put together a formal Marine wedding ceremony.

An ex Marine who is also a journalist is assigned to Rice's unit to do an article on the modern Marine core. Rice quickly discovers not is all as it should be in the situation.

Rice returns to his home town to aid in the burial of a Marine killed in a training accident. He has to deal with the grieving family of the boy as well as the changes that have occurred since he has been away.

Rice loses his girlfriend to a Naval Academy football All-American, who also happens to be the nephew of the colonel.

A young sergeant is being evaluated for officer training, but unexpectedly it's revealed that his mother is a communist agent and she's in town to pitch a rabble-rousing speech at a rally where she will denounce the Marine Corps for not immediately elevating his rank, against his wishes. It falls on Rice to determine what will be done with the sergeant.