Martin Sheen, who plays Attorney General Robert F. Kennedy, went on to play American President John F. Kennedy in the mini-series Kennedy (1983).
The title is a reference to the book "The Guns of August" by Barbara Tuchman, which had greatly impressed President John F. Kennedy and from which he drew inspiration in dealing with the Cuban Missile Crisis.
William Devane plays John F. Kennedy, and Martin Sheen played a member of his Cabinet. In the television series The West Wing (1999), this was the reverse, with Sheen playing the American President, and Devane portraying a member of his Cabinet.
Originally shot on videotape, and first shown in this format, but when it was sold to local stations, it was transferred to film.
Based on a book by Robert F. Kennedy called "Thirteen Days: A Memoir of the Cuban Missile Crisis". The theatrical film Thirteen Days (2000) has the same title as Kennedy's book and is about the same subject, but it is not based on it.