As the question implies, Ernest Hemingway’s short story “The Night Before Landing” is autobiographical. It’s based on Hemingway’s real-life experience aboard the Chicago, which was traveling toward World War II fighting in Europe. Like Nick Adams, Hemingway was a part of the Italian front. More so, just as the boat in the story zigzags to avoid enemy German submarines, the boat in real life zigzagged to preemptively thwart German submarine attacks.
Now, it’s important to be aware that Hemingway didn’t intend to publish this piece of writing as a short story. “The Night Before Landing” was supposed to be a part of a novel that Hemingway had tentatively titled Along with Youth. A decade after Hemingway died, the Hemingway scholar Philip Young included this piece in a posthumous collection of Hemingway’s work called The Nick Adams Stories.
If Hemingway himself had had the chance to ready the text for publication, he might have changed the names. It appears as if the names used in the story are the names of the people in real life. In a letter to his family about his experience on the Chicago, Hemingway tells them that he’s been
paling with two polish Lieutenants. Count Galinski and Count Horcinanowitz although it is not spelled that way.
Thus, Anton Galinski seems to be Leon Galinski, and Count Horcinanowitz (whose name Hemingway admits to misspelling) is Leon Chocianowicz. It’s possible that Hemingway changed Galinski’s first name to Anton so as not to confuse readers.
Finally, Galinski and Chocianowicz aren’t the only two characters whose names derive from real life. There was an actual Gaby on the ship, and “the Carper” was the actual nickname for Hemingway’s friend Howie Jenkins.