In terms of theme, "The Soldier's Home" seems to "answer" another Hemingway story, "In Another Country." "In Another Country" shows the loneliness and isolation of a young American soldier at war in a foreign country. "The Soldier's Home" shows the loneliness and isolation of a young American soldier, Harold Krebs, who has come home from war.
The story tells of Harold's struggle as he tries to pick up his life in his home town after returning from combat in World War I. He moves back into his family's home and tries to resume some of his old activities, but Harold finds that everyone has moved on in his absence. His former classmates have changed; more importantly, however, Harold finds that he has changed in ways neither his family nor friends could possibly understand because they have not been where he has been or seen what he has seen. He has no one with whom to share his true thoughts and feelings; no one is really interested in hearing them. As Harold's parents, particularly his mother, continue to treat him as the boy he used to be, his resentment, frustration, loneliness, and sense of isolation overwhelm him. Realizing that he belongs nowhere, Harold chooses to be lonely in the anonymity of a big city instead of his small home town. He decides move on to Kansas City, leaving home behind, permanently.
This theme of alienation in the story is perhaps most significant because it is reflected in so many of Hemingway's works, including his vignettes and novels, as well as other short stories.