The Narrator is an unnamed American officer who sustained injuries while volunteering for the Italian Army during World War I. He undergoes mechanical physical therapy on his wounded knee and spends his evenings socializing with other recovering officers. He possesses a practical awareness of his own limits, openly admitting to himself that he lacks the aggressive, fearless instincts of his combat peers. Despite his injuries, he maintains an optimistic outlook on his future and expresses a desire to marry.

The Major is an older Italian officer who was recognized as the greatest fencer in Italy before a war injury left his hand severely withered. He sits next to the narrator during physical therapy and assumes the role of an exacting tutor, correcting the younger man's Italian grammar. He projects a deep cynicism regarding emotional attachments and strictly warns the narrator against marriage, arguing that a man should never place himself in a position to lose what he values most.

The Young Italian Soldiers are a group of recovering officers receiving treatment at the same hospital. Three of them are highly decorated fighters from Milan who bonded over their aggressive combat experiences in the trenches, including one who served as a lieutenant in an elite commando unit. The fourth is a younger boy from a prominent family who suffered a severe facial wound on his first day at the front. They join the narrator for evening outings, though their varying degrees of battlefield glory create a silent barrier between them.

The Major's Wife is a young woman who recently wed the older officer. The couple intentionally delayed their marriage until they were absolutely certain the major was permanently removed from the immediate dangers of the frontline. She stands as the focal point of the major's intense emotional vulnerability and serves as the primary reason for his vehement warnings against romantic attachment.

The Doctor is the medical professional operating the experimental physical therapy machines at the Milan hospital. He attempts to boost his patients' morale by making highly optimistic promises about their physical recoveries, assuring the narrator that his injured knee will heal well enough to play football again. He uses before-and-after photographs of successful treatments as theatrical props to encourage the wounded men.