What kind of person was Harold Krebs before the war in Hemingway's "Soldier's Home"?

While there is not much evidence to say for sure what Harold Krebs was like before he went off to war, it might be safe to say, judging from the text, that he was probably a conformist and an idealist. In the very first paragraph Hemingway describes a photo of Krebs with his college fraternity. He notes that all the young men looked the same:

There is a picture which shows him among his fraternity brothers, all of them wearing exactly the same height and style collar.

Krebs conforms to what was expected of him. He goes to a religious school, joins a fraternity and is part of the masses. There is nothing to distinguish him from any of the other men who attended his college or eventually went off to war. It's also possible that he conformed to the prescribed religion of his family. At the end of the story his mother asks him to pray with her. It may have been commonplace before the war for him to kneel with his mother and pray. After the war Krebs has lost his religious devotion.

The text indicates that Harold was an idealist. Rather than waiting to be drafted when the United States entered World War I in 1917, Hemingway writes that Krebs enlisted in the Marines, often thought of as the elite of American fighting forces. He may have been swept up by the wave of nationalism that gripped the country leading up to its entrance into the war. 

Before the war he was interested in the normal things that boys his age would have invested their time in, such as going out with girls, spending time with his young sister, playing pool and hoping that his father would allow him to use the family car. This normal American, however, is forever changed by the war. He no longer has the social energy to associate with girls, he talks to his family very little and is even apathetic toward his younger sister whom he was obviously quite close to before the war.