According to director Oliver Stone, there was a dinner where James Woods (Richard Boyle) and Jim Belushi (Doctor Rock) met their real life counterparts. In Stone's words, Belushi stormed out of the dinner in a rage, while Woods did not get along with the real Boyle.
Oliver Stone had a very hard time getting funding for this film. He was forced to put a second mortgage on his house to get finance until British producer John Daly pledged his support to the project. The film was made on a budget of just under five million dollars.
According to James Woods he went to see the film at a local theatre, and while he was leaving, a refugee from El Salvador knelt before him and kissed his hand, thanking him for telling the story of her family's massacre.
When James Woods discovered that there was a blank cartridge in the rifle which could have damaged his head, he refused to continue with the scene, resulting in another of the many fierce arguments between cast and crew.
At the 1987 Academy Awards, Oliver Stone had two pictures in contention, this movie and Platoon (1986). This film had two nominations, the other had eight, giving Stone a combined total of ten nominations from two movies, both war films and both with one word titles. Salvador (1986) failed to win any Oscars, but Platoon (1986) took home four including Best Picture.
Martin Sheen was originally cast as Richard Boyle. James Woods was originally offered the part of Doctor Rock. But Woods convinced Oliver Stone that he would be better in the lead role. Sheen, who was uncomfortable with the material, agreed and allowed Woods to take the role.
Although Marlon Brando was Stone's first choice, he also offered the lead role to Paul Newman and Lee Marvin. Newman liked the project, but had so many other interests to take that he could not fit it into his schedule. Marvin also liked the script, but felt he was too old for the role and also did not want to travel as much as the film required due to his health problems. Marvin died the year after the picture was released.
The movie refers to "Cédulas". Also spelled as Cedulas, the term is short a form for "Cédula de Identidad" or "Cédula de Ciudadanía". They are also known as "Documento de Identidads" (DNI). Characters in the film explain them to be voting papers or birth certificates but a fuller definition of Cedulas explains them as being identity papers or national identity documents. Cedulas, which are by literal definition some form of an order or authorization, are used in quite a number of Latin, Central and South American countries such as El Salvador. Cedulas can also refer to an identity document's number.
Near the end of the film, there is a massive cavalry charge by the rebels. According to Jim Belushi (who plays Doctor Rock in this film) director Oliver Stone forfeited his $25,000 paycheck to pay for the scene with the horses.
One of a number of Latin American related movies made by Hollywood in the 1980s that Mexican actress Elpidia Carrillo appeared in, others being Beyond the Limit (1983), Under Fire (1983) and The Border (1982), Capillo's part in the latter having been said to have been very similar to her role in this movie.
Orion Pictures was initially to distribute the movie, but out of concern of the film's grim ending, the studio backed out, and the producers at Hemdale Film Corporation released it themselves. An Orion executive admitted later that the decision was a mistake.
Richard Boyle revealing the last roll of film from his boot heel was improvised by James Woods. Oliver Stone was furious with him, as it was the last shot they needed to film and could only get one take. However, Stone kept the scene in the final product, and later admitted to loving the scene.
The film's closing epilogue states: "To date the murderers of Archbishop Romero have not been found and the same military leaders continue in power. Salvador continues to be one of the largest recipients of U.S. military aid in the world".