The actor who played young Ron Kovic, Bryan Larkin, was originally from Massapequa, NY, the town the very character he was playing was from and where the bulk of the movie takes place. Of course, most of the movie was filmed in Texas, including the young Ron Kovic scenes. So, Bryan Larkin left his hometown of Massapequa for Texas to film scenes that are meant to be in Massapequa.
A copy of "Johnny Got His Gun," a popular anti-war novel about WW1, is visible on Ron's hospital bed when he learns he will never walk again. In the novel, the main character is a soldier who is mutilated beyond recognition in a war; he has lost both of his arms and legs as well as his sight and hearing.
Oliver Stone and Tom Cruise both expressed interest in using a nerve agent to cause genuine paralysis in Cruise's legs, but they were unable to find a substance that was safe enough to guarantee no permanent damage.
During the demonstration, one of the speakers says that the Bronze Star and Purple Heart honors he earned in Vietnam mean nothing. These are the same two honors that director Oliver Stone and the real Ron Kovic received after serving in Vietnam.
Oliver Stone's then wife Elizabeth is mentioned in the closing credit roll as Naijo No Ko. This Japanese term means "with the help of my wife" or, more colloquially, "I owe my success to my better half".
This film represents one of the rare instances where Oliver Stone was able to cast his very first choice for a starring role in one of his motion pictures. Tom Cruise was Stone's definite preference for the role of Ron Kovic, a casting decision that Kovic ultimately stood by.