The lines spoken by Colonel Montgomery to the outraged Colonel Shaw when he orders the burning of Darien - "Secesh has got to be swept away by the hand of God like the Jews of old" - are the actual words of Montgomery, quoted in a letter from the real Shaw to his family.
Very early in the movie there is a scene of Union soldiers playing baseball. While there remains considerable dispute about exactly when, where and how the sport was invented, there is no question that the Civil War itself had a significant role in the rapid growth of the sport, as it became a popular pastime for soldiers on both sides of the Mason-Dixon line who spread it around the country. Incidentally, Union general Abner Doubleday once was credited with inventing baseball but that theory has long been discredited.
The film depicts the 54th Massachusetts Volunteer Infantry training through the Christmas holidays of presumably 1862 (after the September 1862 Battle of Antietam), but the real 54th Massachusetts did not organize until March 1863, and were engaged in their first battle on James Island, South Carolina on 16 July 1863, and then Battery Wagner (the final battle in the film) on 18 July 1863.
This film has one of the longest credit rolls in history. The credits following the movie ran a full ten minutes and were shipped to theaters on a separate reel. The films cast is displayed three times, each in a different layout.
Several of the extracts from Colonel Shaw's supposed letters to his mother, as heard in voice-over narration throughout the film, were actually taken from "Army Life in a Black Regiment," an 1870 book by Thomas Wentworth Higginson, who commanded the 1st South Carolina Regiment during the Civil War.
Many scenes/subplots were cut out from both the theatrical version and the DVD. These include Shaw (Matthew Broderick) and Cabot Forbes (Cary Elwes) attending school together, fencing one another, etc. Nearly all of the scenes of Jane Alexander were cut.
Many of the first shots of the movie were taken from the 125th anniversary reenactment of the Battle of Gettysburg in 1988, in which up to 15,000 participants took part. The scenes filmed at the Gettysburg Reenactment were fused into the depicted Battle of Antietam scene which was filmed in Mcdonough, Georgia. Viewers can distinguish the two separately filmed locations either by the massive amounts of reenactment troops that were at the Gettysburg event; or by the browner dry summer background of Pennsylvania in 1988, and the greener spring background of Georgia in 1989.
In order to simulate realistic shell bursts, Edward Zwick and his effects crew used lycopodium powder, which, when puffed into a naked flame, instantly ignites producing a phosphorescent ball of light for a split second.
The inaugural battle for the real 54th Massachusetts was at James Island, South Carolina, on 16 July 1863. The scene depicting this engagement was filmed during late February of 1989 at the Girl Scout Camp on Rose Dhu Island near Savannah, Georgia. It actually snowed during filming, and heaters had to be brought in to melt the snow. Later, in the Christmas at Camp Readville scene (filmed in March 1989 at the old Train Roundhouse in Savannah, Georgia), snow blowers were brought in to blow chipped ice onto the ground to give the appearance of a winter snow.
Alhough the respected film history periodical "Films in Review" usually devoted itself to film history, it released a two-part article on "Glory" by Charles Sawyer, who was an extra in the movie, in its December 1989 and January 1990 issues.
The trivia items below may give away important plot points.
At the end, Shaw is thrown into the mass grave with the other black soldiers. Normally officers were given formal burials. The Confederacy had such contempt for the black regiment that the officers were thrown in with the regular soldiers and no honors were rendered.
In the attack to the Fort Wagner nearly half the regiment was killed, wounded or captured. For his bravery in the battle, Sergeant William H. Carney became the first African American to earn the Medal of Honor, the nation's highest military award. However, the award was given to him 37 years later.
The film's epitaph that Fort Wagner was never taken is not quite accurate. Following the failure of the July 18, 1863 attack by the 54th Massachusetts and other regiments, Union Major General Quincy Adams Gillmore laid siege to the fort. For two months, Union regiments dug a series of zigzag trenches on Morris Island, bringing long-range artillery guns closer and closer to Fort Wagner. During the siege, the Confederates in the fort discovered that their water wells had been poisoned by the decomposing bodies of Union soldiers buried in nearby mass graves. After an intense two-day bombardment by Union artillery, the Confederate Army was forced to abandon Fort Wagner on the night of September 6, 1863. The following morning, Union soldiers entered the deserted fort. Today, a large part of what remains of Fort Wagner is under water, thanks to erosion from the sea.
In real life, it was Brigadier General George Crockett Strong (played by Jay O. Sanders in the film) who addressed the 54th Massachusetts on the beach before their assault on Fort Wagner. General Strong, the brigade commander, pointed to the 54th's flag bearer as asked, "If this man should fall, who will lift the flag and carry it on?" It was Colonel Robert Gould Shaw who replied, "I will!" General Strong was himself mortally wounded by shrapnel in the assault on Fort Wagner. He was taken to New York City, where he died of tetanus two weeks after the battle.
Robert Gould Shaw and Charles Fessenden Morse were the only two soldiers whose real names were used in the movie. Morse, however, was not in the 54th in reality. Cabot Forbes was based off of Edward Needles Hallowell, who led the 54th after Robert died.