Mary, like her son, is intelligent and sensitive. We can see her intelligence through her enlightened views about black people: throughout the novel, she encourages Rufus not to treat blacks any differently than he would anyone else. Mary is a kind, giving person, and very loving to her children. Her family appears to feel that she married beneath her status; Agee implies that she has a more genteel background than Jay does. However, Mary and Jay, when together at the beginning of the novel, appear to have a happy marriage with relatively little strife. There are allusions throughout the novel to a drinking problem that Jay used to have; Mary herself wonders for a moment if Jay was drunk when he got in his accident, but then she banishes the thought from her mind. Drinking heavily, it seems, has not been a problem for Jay since before the children were born; Agee presents it as a fairly resolved problem, but one that has left lasting fears and uncertainty.
Religion is of the utmost importance to Mary, yet her religious beliefs become a point of contention between her and her husband and the rest of her family. From the beginning of the story, it is clear that she is more religious that Jay, and furthermore that she is afraid of a rift growing between them due to their differing beliefs. The only one in the family who can sympathize with Mary's religious tendencies is Aunt Hannah, but even Hannah is not quite as fervent as Mary. After Jay dies, religion becomes even more important to Mary; she cannot understand how else to cope with the death. We get the sense that religion is something that separates Mary from her children. There is no logical reason for the children to believe in God, and meeting Father Jackson at the end of the story is not likely to make them any more inclined to believe that there is a God—least of all a kind one, if unsavory men like Father Jackson can represent him.