Arthur Bach is a rich socialite from a financially powerful English family, based in the New York City area. Though his family has built great prestige for themselves, Arthur is an embarrassment. He cavorts with women, including prostitutes, he drinks heavily and is often seen publicly inebriated, and consistently makes a spectacle of himself, which is often documented in newspapers and tabloids. Arthur's father and his grandmother demand that Arthur marry a woman named Susan Johnson, herself the daughter of another powerful businessman, Burt Johnson.
The marriage would lead to a lucrative business partnership between Arthur's father and Johnson and would secure Arthur's sizable inheritance. Arthur, however, does not love Susan and is depressed because he feels he's being coerced. One day, while in Bergdorf-Goodman's store in Manhattan Arthur spots a young woman, Linda Marolla, stealing a necktie (a birthday present for her unemployed father). One of the store's security guards follows her outside and Arthur and his servant, Hobson, follow them as well. Linda quickly makes a scene when the guard accuses her of the theft, but Arthur steps in and covers for her, saying she was buying the tie for him.
The guard is apologetic and leaves. Arthur kisses Linda in front of a crowd to continue the ruse, and then asks her for her phone number. He also offers his limo and chauffeur, Mr Bitterman, to Linda to get home. Arthur takes Linda out on a date and the two instantly fall for each other. Arthur meets later with his father, who expresses his disappointment at Arthur's reputation as a rich playboy.
Arthur tells his father that he refuses to marry Susan, at which point his father threatens to cut off his inheritance of $750 million. Arthur acquiesces and takes his mother's engagement ring to give to Susan. Arthur later meets with his grandmother, Martha, the Bach family matriarch, who tells him the same thing his father did: she'll cut him off if he doesn't marry Susan. She also suggests that while he's married to Susan, he can still see Linda on the side. Arthur, however, does not want to carry on an unfaithful relationship with Linda but still agrees to marry Susan.
Arthur later discusses the matter with Hobson, with whom he has a closer relationship than his own father. Hobson tells Arthur to respect his family's wishes and marry Susan. Hobson, however, recognizes that Arthur is indeed in love with Linda. Before leaving to pick up Susan to propose to her, Arthur calls Linda and tells her the truth. Linda seems mostly unfazed by the news, however, her father breaks down at the thought of her daughter missing the chance to marry a millionaire. At Burt Johnson's house, Arthur talks to Johnson himself, who tells the young playboy that he doesn't approve of his excessive drinking. He also explains a bit about his upbringing, relating a story about how he killed a burglar at the age of 11.
To Johnson, the most important thing in his life is Susan, and he would kill to protect her. Susan and Arthur go to a posh restaurant where Arthur proposes to her. Though Susan knows about Arthur's philandering and drunkenness, she still will marry him. Arthur takes Susan home and then drives to Linda's apartment very late at night and even drunker than he was at dinner. He offers Linda $100,000 for her trouble, which she refuses and orders Arthur to leave.
The next day, Arthur has a brief argument with Hobson concerning his future. Arthur, who has been mostly passive all his life, apologizes to Hobson for raising his voice. Hobson takes Arthur's attitude to heart and visits Linda and her father. He tells Linda that Arthur and Susan's engagement party is being held at Arthur's family home in Southampton, Long Island. He also gives her a stylish dress to wear, knowing that she'll go.
Right before he leaves, Hobson coughs and seems weak, but he dismisses Linda's questions about it. Linda arrives at the engagement party and, when she sees Arthur singing to his fiance, begins to flirt with another guest, claiming she'd met him before. Arthur sees her there and sends the bewildered man away to get them drinks. Arthur takes Linda on a tour of the house and they end up in the horse stables. Their conversation proves that they are still in love with each other.
When Susan interrupts, Linda tries to cover for Arthur by saying she'd come to beg him for money, however, Susan brings unhappy news: back in New York, Hobson has been taken to the hospital and his very ill. Arthur leaves immediately to see Hobson. At the hospital, Arthur tries to make things as comfortable as possible for Hobson, bringing in his own bed, having meals delivered from expensive restaurants, buying him presents and staying in the hospital room with him. Arthur also has the wedding postponed. During the time he cares for Hobson, Arthur stays sober and stops his philandering and excessive spending, having spent a large amount of his own money to keep his friend comfortable.
Hobson eventually dies, causing Arthur incredible grief. Arthur goes to a small bar and becomes incredibly drunk a few hours before the wedding. He goes home and dresses for the wedding and, still drunk, visits Linda at the diner where she works as a waitress. Arthur asks her to marry him, despite the fact that he will lose his inheritance and be poor.
Linda agrees and she agrees to go with him to tell Susan. Arthur is late arriving at the church. He finds Susan in one of the back rooms and tells her he doesn't love her. Susan becomes upset and calls for her father, who begins to beat Arthur up. Linda arrives. trying to protect Arthur, however, Johnson, grabbing a small cheese knife, starts after Arthur and Linda.
Suddenly, Martha Bach appears and slaps Johnson, bringing him out of his murderous rage. Arthur walks out to the dais in the church and tells everyone that the wedding is off and that he'll likely not see many of them again because he'll become poor when his family cuts off his inheritance. He collapses in front of them. After all the guests have left, Arthur and Linda talk on the dais, while Martha listens from the pews. Arthur promises to be faithful to Linda and begins to talk about finding a job when Martha interrupts and says that no heir of her family will ever be working class. She tells Arthur that he can have his full inheritance and can stay with Linda. At first, Arthur refuses, but accepts. He then has Bitterman drive him and Linda through Central Park together.