A statue of Father Francis Duffy stands in Times Square in New York City.
In training camp, there is a reference to the 69th as "Coxey's Army". This was the name given to a protest march on Washington in 1894 by unemployed workers, led by businessman Jacob Coxey.
The "Major Donovan" character was based on "Wild Bill" Donovan, who won the Medal of Honor in World War I, and as Major General Donovan was the Director of the Office of Strategic Services (OSS, forerunner of the CIA) in World War II.
The poem read at the funeral of the soldiers killed in the dugout is"'Rouge Bouquet" by Joyce Kilmer (portrayed by Jeffrey Lynn). This scene and preceding ones are based on a true incident in the war, when a German heavy artillery bombardment on March 12, 1918, buried 21 men of the 69th; 14 of the bodies were never recovered.
"Lux Radio Theater" broadcast a 60-minute radio adaptation of the movie on
April 6, 1942, with Pat O'Brien reprising his film role.