Lily Bart  -  Lily, the novel's protagonist, is an unmarried 29-nine-year-old woman who desires to be a social success. Her mission is to marry a relatively wealthy man, thereby ensuring her financial stability and a place in the higher levels of New York society. Unfortunately, though, her desire to marry someone wealthy clashes with her feelings for Lawrence Selden, a man of modest means whom she truly loves. She also suffers from an inability to make decisions, which causes her to pass up several good marriage opportunities in hopes that she can do better. Book Two chronicles Lily's gradual expulsion from society after a false rumor spreads that she has had an extramarital affair. She eventually joins the working classes before dying at the end of the novel from a sleeping medicine overdose.

Lawrence Selden  -  Selden is a detached observer of the New York society that Lily aspires to join. He is a lawyer by profession, but he is not particularly wealthy, which prevents Lily from marrying him even though they love one another. Throughout the novel, Selden struggles between his desire to remain detached from society and his wish to court Lily and convince her to marry him. At the end of the novel, he resolves finally to propose marriage to Lily, but his decision comes too late—he finds her dead in her apartment.

Bertha Dorset  -  The wife of George Dorset. Most of the characters (including perhaps her husband) know that she has a history of extramarital affairs, one of which may have been with Lawrence Selden. She is described as a nasty woman who enjoys making other people miserable, especially her own husband. She invites Lily on a cruise with her, her husband, and Ned Silverton around the Mediterranean, but only so Lily will distract George while Bertha has an affair with Ned. Bertha, the novel's antagonist, spreads the rumor that Lily and George are having an affair, then uses her money and influence to keep Lily out of society forever.

Gerty Farish - Gerty is Selden's cousin. She is a kind, generous woman who does a lot of charity work. In Book Two, she becomes one of Lily's only friends, giving her a place to stay and taking care of her when everyone else abandons her.

Simon Rosedale - Rosedale is a dedicated social climber who owns many stocks and lots of property. At the end of the novel, he asks Lily to marry him, an opportunity that she passes up at first. Later on, he becomes her friend, and visits her after she becomes very poor and very sick.

Gus Trenor  -  Trenor, the husband of Judy, is a lonely, moody man who has a particular liking for Lily even though he is married. In Book One, Lily asks him to invest her money for her in the stock market. Instead, Trenor invests his own money and gives Lily the profits. When Lily finds out that the money is not truly hers, she resolves to pay Trenor back rather than agree to be his friend.

Percy Gryce - Gryce is a young, rich, eligible bachelor on whom Lily sets her sights early in the novel. Unfortunately, just as Lily decides she must marry him, he announces his engagement to Evie Van Osburgh. He is another missed opportunity for Lily.

Judy Trenor  -  Judy, a close friend of Lily's, is the social overseer of the events at the Bellomont, her out-of-town estate. She regularly hosts large bridge parties and gives Lily a place to stay for up to weeks at a time. She all but disappears in Book Two.

Carry Fisher - Carry Fisher is known for bringing newcomers, such as the Brys, into society. After Lily has been expelled from the upper class by Bertha, Carry is one of the few people who still shows compassion toward her, offering Lily support and money.

George Dorset  -  The husband of Bertha, George does not factor into the novel regularly until Book Two, when he begins to realize that his wife is cheating on him with Ned Silverton. To complicate the matter, George seems to fancy Lily, although she will not ever see him again after people spread rumors that the two of them had an affair.

Ned Silverton - Ned accompanies Lily and the Dorsets on their Mediterranean cruise. A young, rich man, he has an affair with Bertha, but manages to keep it concealed from most of society.

Mrs. Peniston - Julia Peniston is Lily's wealthy aunt who lives on Fifth Avenue. Mrs. Peniston became Lily's guardian after Lily's mother dies. When Mrs. Peniston hears the rumors that Lily had an affair and learns that Lily gambles on Sundays, she disinherits her before her death at the beginning of Book Two, and leaves most of her estate to other relatives.

Jack Stepney and Gwen Stepney  - Jack is Lily's cousin. He married Gwen Van Osburgh in Book One, and is a regular member of society. In Book Two, he agrees to shelter Lily for the night after she is kicked off the yacht by Bertha. Jack and Gwen are a very wealthy couple.

Grace Stepney - Lily's competetive cousin. When Lily asks Grace for financial assistance, Grace flatly refuses.