One could argue that the traditional, chauvinistic American society of the late 1800s is the primary antagonist in the story—it is an oppressive, controlling force on Louise Mallard, who feels stifled in her marriage and mundane life. The story's central conflict revolves around the sudden death of Brently Mallard, her husband, and includes Louise's response to the shocking news. Louise learns that her husband died in a railroad accident and goes upstairs to grieve by herself. Once Louise is in her upstairs bedroom, she notices the peaceful spring day and contemplates her future without marital obligations or bending to her husband's will. As Louise daydreams about her future as a widow, she is overcome with joy and experiences a sense of freedom for the first time.

Louise's epiphany underscores the repressive nature of marriages in the period. As a woman, Louise Mallard was expected to sacrifice her personal freedoms and behave like an obedient, passive housewife. Society expected Louise to be completely dedicated to Brently and she was treated like a second-class citizen. Although Brently meant well, Louise desires to experience an independent life and is filled with hope for a better future following his "death." After Louise's epiphany and newfound hope, she walks downstairs, where she discovers that Brently is alive. Upon seeing Brently, Louise realizes that her dreams are shattered and dies of a heart attack.

In The Story of an Hour, the story's central conflict is the main character's shock at the discovery of her true inner feelings after being announced about the death of her husband. She did not expect, from what one perceives in the story, that she would actually welcome the situation. Her feelings shocked her, because she for the first time felt freedom and a sense of joy at being "released" from her role as submissive wife. In the end, when he comes back and we find out that he is actually alive, she cannot take the change, nor fathom the idea that those feelings she had been bottling up for ages, and now they are out- only to be put them back in again which is why she passes out and collapses.

Hence, in this story, the unique antagonist would be the protagonist herself, or better yet, her submissive nature as an enslaved wife, and the role that she, herself, opted to take as a woman.

In The Story of an Hour, the antagonist would be Mr. Brentley Mallard, Mrs. Mallard's husband.  The central conflict revolves around Mrs. Mallard being informed that her husband has been killed in a train accident.

After learning of this news, Louise Mallard goes upstairs into her room and sits in a chair facing a window and begins to imagine the life she will have as a widow.  Up until that moment, she never imagined that she would ever have any individual freedom in her life, since, in this period in history, women were considered the property of their husbands and could not go out without them.

"Chopin deals with the issues of female self-discovery and identity in "The Story of an Hour." After Mrs. Mallard learns of her husband's death, she is initially overcome with grief. But quickly she begins to feel a previously unknown sense of freedom and relief."

Mrs. Mallard has lived a life that has largely been controlled by Mr. Mallard's wishes and choices.  She has loved her husband, she tells the reader, most of the time, but she has not loved the confining feeling that marriage has given her. She longs to make her own decisions, choices, to explore her own interests, just the thought of having the ability to make such choices makes her feel joyful.

"Louise is ecstatic when she realizes that ''there would be no powerful will bending hers in that blind persistence with which men and women believe they have a right to impose a private will upon a fellow-creature." 

Her joy, however, is short-lived, when at the end of the story she gets a great shock, a surprise that causes her to die on the spot, her husband walks in the front door, very much alive.  All the free days she imagined she would have, sitting upstairs in her chair, thinking of herself as a widow, free from the demands of marriage, are gone in an instant.  In that same instant, Louise Mallard's weak heart gives out and she dies. 

She dies a happy death, having had the opportunity to explore, even if it is only in her mind, what life would be like freed from the constraints of marriage and the control of her husband.  

"Chopin seems to be making a comment on nineteenth-century marriages, which granted one person—the man—right to own and dominate another—the woman. This theme, unpopular in an era when women were not even allowed to vote, is examined in many of Chopin's other works, most notably The Awakening."