A coming-of-age tale like The Great Santini inevitably centers around themes of maturity, acceptance, and transformation. The story chronicles Ben Meecham's journey as he navigates these experiences, some with more grace than others. Conroy also highlights the theme of duty through Ben's struggle to meet his father's impossible expectations. Just as Bull shows unwavering loyalty to the Marine Corps, his children feel a similar allegiance to him, at least until they reach a certain age. Ben observes his mother fulfilling her role as a Marine wife, constantly at her husband's disposal, while she strives to maintain harmony at home despite Bull's relentless perfectionism. The novel explores survival and the familial bonds that aim to support Bull's family members as they endure his bullying, criticism, harassment, and violence.

Catholicism takes a prominent role in The Great Santini, not because Bull is a devout follower, but because Lillian is. Bull, who lacks spirituality in the traditional sense, views the church as a kind of training ground for his children. He occasionally reflects "about the relationship of Catholics and the military," suggesting that Catholics, accustomed to following the Pope's orders, make good soldiers. During a Christmas Eve service, Bull observes that "The Church is the structure wherein laws are administered. The Church and the Pentagon are alike in that respect." For his personal prayer, Bull adds, "O Lord, make me worthy of the squadron I command and please give me the chance to kill Castro." Bull sees no disrespect in these thoughts, and Conroy highlights deep irony by comparing Bull's two guiding beliefs.

Religions frequently appear as a theme in Conroy's fiction. These religions can encompass any repeated actions or rituals that provide focus in a character's life. Bull reveres the Marine Corps, while Lillian embraces both her Catholic faith and the religion of manners and decorum. Lillian Meecham epitomizes the Southern woman, constantly urging her children to be polite and maintain an appropriate demeanor. When Bull returns to the states after a yearlong overseas tour, Lillian instructs her children: "Stand up straight, Ben and Matt. Shoulders back. Like Marines. Matthew, let me comb your hair. Girls, check your makeup, we want to be beautiful for your father. When he gets off the plane, we'll all run to meet him . . . Then say, 'Welcome home, Colonel.'" Lillian not only provides her children with a catechism of behaviors but also supplies the dialogue. For Lillian, manners become a way to counteract her husband's harsh influence on their four children, and she is committed to maintaining peace at any cost. Instead of trying to change Bull's behavior, she trains her children in self-preservation against their father's all-too-predictable moods.

The demands of sports offer Ben the same comfort and protection. Conroy highlights the challenges of frequent moves for military families and the impact this can have on children. Ben manages to overcome the loneliness of being "the new kid" through his involvement in sports. He remains nearly unnoticed until basketball season arrives, when he knows he will suddenly become popular. Conroy uses this positive aspect of Ben's life to illustrate how Bull lives up to his name by bullying his children. A one-on-one basketball match between Bull and Ben showcases the older man's stubborn determination to always be the best, to the extent that he cannot appreciate his son's talent and growth.

In Conroy's novels, readers can often anticipate a strong focus on the theme of racism, and The Great Santini is no exception. Early in the school year, Ben's sister, Mary Anne, urges Ben to defend a Jewish classmate, Sammy Wertzberger, who is being bullied...