Blanche DuBois is a complex individual who provokes strong reactions from the other characters. We know that she has been a schoolteacher in Mississippi but was asked to leave her job because of an involvement with a student, that she was once a Southern belle from a wealthy family, and that she has a failed marriage and dubious past from which she has fled. Her complexity comes not from her history or background, but from the varied and often inconsistent facades she presents. At once strong in her desires and determined in her claims on the men who are around her, and yet weak and forever looking for someone to take care of her, she gives off a series of conflicting signals. She is neurotic, psychologically deluded about her beauty and attractiveness, and perhaps also an alcoholic. Her sexual desires come through clearly from behind her talk with Mitch about keeping her reputation: when we see her flirting with the young man who calls at the door, we realize just how split her desires are from her surface talk and behavior. This point is made visually in the opening scene where the dainty and beautifully dressed woman who appears leads us to expect quite a different character to emerge than the brittle woman running from her past who begins to display her neuroses and obsessions during the course of the following acts.

Underneath Blanche's quite calculating exterior, there is always a hint of hysteria. In her stories about Belle Reve or her tales of previous lovers, there is something edgy in her conversation, a threat of something that might erupt if she is not handled carefully. This disjunction between emotional surface and depth is brought out throughout the play in the way that Blanche cannot face up to her past, but only reveals glimpses of it through her neurotic behavior and occasional comments. For example, she is forever taking baths as if to clean her conscience, but continues to talk about her past actions in terms which suggest that she has no conception of their moral implications. Admitting, for example, that it is her affairs which have led to her losing her job and being ruined financially, she can only ask Stella, in a roundabout fashion, "Haven't you ever ridden on that streetcar [named Desire]? ... It brought me here." In similarly oblique terms, she describes a passionate affair as "someone you go out with—once—twice—three times when the devil is in you." Her flirtation with Stanley and the man at the door also suggest that she does not have the self-awareness to realize that what she is doing here is no different from the things she has done in the past which she claims to regret so much.

Not only does Blanche lack self-awareness, she is also utterly self-centered. As a house-guest in a small apartment, her behavior is intensely irritating. (If David Mamet's play Oleanna could be described as a play about a man who needs an answering machine, A Streetcar Named Desire is a play about a man who needs a guest room.) Not only must Blanche's presence disrupt Stanley and Stella's sexual intimacy, but it also spoils the routine of their everyday life, particularly because she is always in the bath when anyone else needs to use the bathroom. The fact that she freely (and dishonestly) drinks Stanley's whisky and that she sends the pregnant Stella off to run errands for her further emphasizes a selfish nature.

Yet, despite her contradictions, dishonesty, inconsistency, and selfishness, Blanche comes across as a sympathetic, if not entirely likeable, character. Williams himself commented that "... when I think about her, Blanche seems like the youth of our hearts which has to be put away for worldly considerations: poetry, music, the early soft feelings that we can't afford to live with under a naked light bulb which is now." Even though her faults are plain to see, Blanche still commands pity. Williams thought that this pity was an important element of the play. In a letter to Elia Kazan, the first director of Streetcar, he answered a question which Kazan had put to him, saying, "I remember you asked me what should an audience feel for Blanche. Certainly pity. It is a tragedy with the classic aim of producing a catharsis of pity and terror and in order to do that, Blanche must finally have the understanding and compassion of the audience. This without creating a black-dyed villain in Stanley. It is a thing (Misunderstanding with a capital M) not a person (Stanley) that destroys her in the end. In the end you should feel 'If only they had known about each other.'" Perhaps part of the reason for this pity is that Blanche's tragedy does not come about only because of her actions, but because of the flaws of society itself. As the old gentility of the South is threatened by modernization and industrialization, and as women's roles become uncertain as they are caught between old ideals of beauty and gentility and the modern toleration of sexual license, Blanche appears to be stranded at a crossroads, with each choice of path risking society's disapproval and her ultimate destruction.

Much of Stanley's character is seen through his relationship with Blanche. Stanley does not seem to have a life outside of the immediate action of the play, but when he is on stage he has a commanding presence, a quality underlined by Blanche's obvious sexual attraction to him. She even jokingly tells Stella that she has been flirting with Stanley to get him to see her side of the story about the loss of Belle Reve. While this may be her motivation, it's obvious that Blanche is genuinely attracted to Stanley and that flirting does not take too much effort on her part.

Blanche's response to Stanley's strong presence suggests that he is some kind of an animal. In earlier versions of the play, Stanley had a gentler, ineffectual side, but in the final writing of Streetcar Williams made him Blanche's complete opposite—angry, animalistic, and reliant on his basest instincts. These qualities are seen most clearly in Blanche's rather patronizing, but highly revealing comment to Stanley that "You're simple, straightforward and honest, a little bit on the primitive side I should think. To interest you a woman would have to ..." The sentence is finished off for her by Stanley, but what we suspect she would have said is what she later says to Stella: that the only way to live with a man like Stanley is to go to bed with him. For Blanche, Stanley's sexual appeal and his primitive nature are closely bound up together. It is from the charge of such opposing feelings as attraction and disgust, expressed in this case through Blanche's eyes, that the play gains much of its energy.

Although Stanley responds in kind to Blanche's flirtations, telling her that ''If I didn't know that you was my wife's sister I'd get ideas about you," we know that actually he despises her and is enjoying the power that comes from being aware of the feelings she has for him. Stanley's actions are what would now be described as ''macho.'' But not only is he violent in his masculinity, he also appears to lack any sense of moral order: his rape of Blanche does not strike him as betraying any moral code, it is simply the outcome of their strained relationship and what he deems to be her inappropriate behavior in the immediate and more distant past.

This action is consistent with his character in the rest of the play and in the events which are meant to have taken place before the play begins. Stanley has power despite his lower social class, but, as he is well aware, it lies in his physical actions. Talking of his wooing of Stella and the difference in their social backgrounds, he comments, "I pulled you down off them columns and you loved it." The social significance of his physical action, like his later rape of Blanche, suggests that the sources of power have changed in American culture and that Stanley is willing to grasp at whatever power he can find in order to assert his place in the family and society around him.

Where Stanley does have an identity independent from that created by the events of the play, he could be said to represent the new social order of modern America as a contrast to the decayed gentility of Blanche's Southern manners. This is also seen in the fact that Williams makes him an immigrant who is proud to be part of the new society of a multi-cultural America. As such an immigrant, he is not concerned about traditions or old hierarchies of land ownership or the power and wealth brought by family positions in society (he appeals instead to the local law of the Napoleonic code to prove that he has been swindled by Blanche's loss of Belle Reve). Stanley's determination to belong to American society and to claim his place there is emphasized by his impassioned outburst in response to being called a "Polack." As he forcefully explains, "I am not a Polack. People from Poland are Poles, not Polacks. But what I am is one hundred percent American ... so don't ever call me a Polack."

Stella appears to be a simple character, but is actually more intriguing than her role as sister and wife to the play's two main protagonists would suggest. She acts as a foil to both characters, allowing their selfishness and emotional failings to be emphasized. She also acts as a measuring stick against which the audience can gauge society's reaction to the events portrayed on stage.

In relation to Stanley, Stella is sensitive and loving, practical and sometimes independent. She clearly loves Stanley, despite his many failings and his violence towards her, and she is willing to accept his temper as part of the passion they feel for each other: "But there are things that happen between a man and a woman in the dark—that sort of make everything else seem—unimportant." She is carrying Stanley's baby, and indeed Stanley's rape of Blanche takes place while she is in the hospital giving birth. In her blinkered loyalty to Stanley at the end of the play and in her willingness to be reassured that what they have done for Blanche is right, her practical nature asserts itself: this is a marriage which she can convince herself she wants to save and will save for the benefit of herself and her child. Whether she is right or wrong to do this is not relevant: what is important to understanding the play is the knowledge that her action is not so unusual. Like many other people in society, Stella continues to function in her daily life despite considerable upheaval. Blanche draws attention to this stoical aspect of Stella's character when she comments, "I never had your beautiful self-control."

Stella's decision symbolizes a greater choice facing American society. She rejects Blanche's strategy of living in a glamorous past and chooses instead the rational, practical, sometimes flawed world which her marriage to Stanley represents.

Mitch is "207 pounds, six feet one and one-half inches" and lives with his sick mother. He is a foil to Stanley: he speaks in a more refined way, he is gentle and restrained while Stanley is rude and sexually forward. Blanche is aware of his kindness and even comments on it, saying, "I thanked God for you, because you seemed to be gentle." Mitch is concerned with proper behavior: in contrast to Stanley, who walks around in his T-shirt and speaks frankly (even proudly) of his sweaty body, Mitch refuses to take his jacket off because he fears he might be perspiring too much.

Mitch's attempted rape of Blanche therefore comes as a shock. The action suggests how male views of female behavior were so idealized that if a man discovered any deviation from accepted norms of virginity and chastity, his reaction would be extreme. Mitch's actions reveal him as a deluded and rather pathetic man who has not fully grasped how relationships work and who has closed his eyes to the fact that men and women can deceive one another.

It is, of course, Mitch's assault on Blanche which leaves her in such a genuinely forlorn state that she becomes vulnerable to Stanley's cruelty and unwanted sexual advances in the later scene. Although Mitch may be upstaged by his more powerful friend, his actions bring about the destructive ending of the play.

Eunice and Steve Hubbell, the landlords residing upstairs from the Kowalskis, offer a glimpse into a potentially future version of Stanley and Stella’s relationship. Eunice is a tough, pragmatic woman often seen as a friend and confidante to Stella. Her marriage to Steve is marked by volatility, swinging between affection and violence.

Despite their turbulent relationship, Eunice and Steve exhibit an element of hospitality and neighborliness. They provide refuge for Stella during her conflicts with Stanley, showcasing a sense of community amidst the chaos. Their interactions reflect the harsh reality of domestic life, set against the backdrop of the cramped living conditions that shape the play’s environment.

The Doctor and Matron arrive at the play's conclusion to escort Blanche to a mental institution. The Doctor, a calm and professional figure, manages to soothe Blanche’s panic, gaining her trust at a critical moment. His demeanor contrasts sharply with the Matron, who is cold and unyielding, embodying the stark reality Blanche must face as she is led away from her fantasies.

Together, they symbolize the societal forces that strip Blanche of her autonomy, marking the end of her struggle to maintain her delusions. The Doctor’s gentle approach underscores the tragic irony of Blanche's dependence on strangers’ kindness, while the Matron’s practicality highlights the unrelenting progression towards Blanche’s inevitable institutionalization.

Allan Grey, Blanche’s deceased husband, casts a long shadow over her life and actions. His suicide, prompted by her harsh confrontation over his homosexuality, is a pivotal moment that haunts Blanche throughout the play. Allan embodies the lost past that Blanche desperately clings to, a time of youthful innocence and love.

His death represents the irreversible loss that propels Blanche into a cycle of guilt and self-destruction. Blanche’s inability to reconcile her conservative views with Allan’s truth becomes a leitmotif of her tragic downfall, illustrating her struggle between reality and the illusions she constructs to protect herself from the painful aspects of her past.

Shep Huntleigh, an imagined savior from Blanche’s past, epitomizes the romantic fantasy she clings to in her deteriorating state. A former suitor who has allegedly made a fortune in the Texas oilfields, Shep is Blanche’s last hope for reclaiming her lost status and security. However, his absence throughout the narrative underscores the futility of Blanche’s dreams.

As Blanche’s mental state declines, her insistence on Shep’s imminent arrival highlights her detachment from reality and reinforces her vulnerability. Shep represents the escape Blanche yearns for—a savior who remains perpetually out of reach, symbolizing the unattainable nature of her desires and the ultimate collapse of her dreams.

Pablo Gonzales is the other player at poker along with Stanley, Mitch, and Steve. He is coarse and loud, a strong, physical character who is, according to the stage directions, "at the peak of [his] physical manhood." He also speaks Spanish.

The Mexican woman appears briefly, speaks only Spanish, and is described as "An old Mexican crone."

The Negro woman is a neighbor whose presence at the opening of the play reminds the audience of the cosmopolitan society in New Orleans. She is vulgar in her conversation, fun-loving and good-humored.

The Nurse who accompanies the Doctor is cold and professional, severely dressed, and speaks in a voice which is "bold and toneless as a fire-bell."

The Young Collector calls to collect newspaper subscriptions. He is polite, reserved, and surprised by Blanche's unexpected sexual advances.