Sergeant Nathan Marx

Marx is the first-person narrator of “Defender of the Faith,” a first sergeant in the Army stationed at Camp Crowder in Missouri. He is a veteran of combat in the European theater of World War II. He is considered the protagonist of the story. During his time in Europe, he experienced the horrors of the Holocaust. Marx himself is Jewish and felt he honored his identity in the war. He is reluctant to disclose this information to Grossbart; eventually, he reveals his familiarity with Judaism and is seen as an “in.” Marx is more sentimental than he lets on. Due to the nature of his position in the military, it is beneficial to shut out tender emotions so as to “shut off all softness [he] might feel for [his] fellows.” Marx says it is easier this way, yet finds himself compelled to attend shul. He struggles to come to terms with Grossbart’s disrespect, but it turns out his initial intuition to dislike him was well-founded. When Grossbart has asked for too many favors under the guise of special treatment, Marx arranges for him to head to the Pacific alongside the other men.

Captain Paul Barrett

Marx’s commanding officer is Captain Paul Barrett. He is described as “short, gruff, and fiery.”

Private Sheldon Grossbart

The antagonist of the story is Private Sheldon Grossbart, an enlisted soldier referred to as "the trainee." Marx takes an almost instant dislike to Grossbart because he sees him as a seeker of special treatment who uses his faith as a lever. As the story progresses, Marx's recognition of Grossbart's scheming deepens, and even as he allows himself to be manipulated, Marx's dislike and disapproval of Grossbart intensify. Marx understands that Grossbart is "goldbricking" or shirking his responsibilities when he asks that the Jewish soldiers be excused from the regularly scheduled Friday barracks cleaning to attend shul. Once he succeeds in getting excused from barracks cleaning, Grossbart becomes bolder in scheming to get different food, a pass to St. Louis for himself and two others, and a preferred, safer posting, all on the pretext that his faith and devotion to his family requires it. 

Larry Fishbein and Michael “Mickey” Halpern

Grossbart's close associates are Larry Fishbein and Michael "Mickey" Halpern, Jewish soldiers who follow Grossbart's lead and reap the benefits of his manipulations. Grossbart, Fishbein, and Halpern are all teenagers and new to the Army. 

Major Ben Ezra

Major Ben Ezra is the chaplain who conducts the Jewish services that Grossbart insists that he, Halpern, and Fishbein desire to attend, though none of the men appear to actually be devout. 

Corporal Robert LaHill

The charge of quarters, or CQ, is Corporal Robert LaHill. 

Sergeant Bob Wright

Sergeant Bob Wright is the non-commissioned officer (NCO) in charge of "Classification and Assignment" (C&A).

Corporal Shulman

Corporal Shulman also works in C&A, and he is another Jew that Grossbart manipulates to attempt to get the posting he wants in New Jersey instead of the Pacific theater, where all the other soldiers are headed. When Marx finds this out, he pulls some strings to send Grossbart to the Pacific theater like everyone else.