After fatally knocking out his opponent in the boxing ring, Irish-American boxer Sean Thornton returns to the place of his birth, Innisfree, Ireland. Seeking a life of quiet and rest, Sean plans to buy "White O'Mornin," his family's old cottage, and keep his boxing identity of "Trooper Thorn" a secret. En route to Innisfree, Sean catches sight of Mary Kate Danaher and is captivated by her beauty. In Innisfree, Sean's meeting with the wealthy widow Tillane, who owns White O'Mornin, is interrupted by the arrival of Mary Kate's brother "Red" Will Danaher, an ill-mannered bully who wants to buy the property himself. Although Will, a neighbor of Tillane's, claims to have been the first to place a bid on the land, the widow sells the property to Sean after Will's presumptuousness annoys her. Later, at the Innisfree pub, Sean's American ways are met with general disapproval, but the parish priest, Father Peter Lonergan, the Anglican Reverend Cyril Playfair and matchmaker Michaeleen Flynn welcome him home. As one of the few Protestants in a community of Roman Catholics, Playfair identifies with Sean's difference from the locals and forms a special bond with him. Their friendship is further cemented when Playfair, a boxing enthusiast, recognizes Sean as Trooper Thorn, but agrees to keep his secret. On his first visit to White O'Mornin, Sean is surprised to find Mary Kate, who has been cleaning the cottage. As the silent Mary Kate tries to flee into the windy night, Sean grabs and passionately kisses her. She returns his feelings, but quickly leaves because Irish custom demands a proper courtship. Although he does not understand the custom, Sean allows Michaeleen to become his matchmaker and Mary Kate happily agrees to a courtship. Because Will is still bitter over the property, he refuses to give his permission, making both Sean and Mary Kate miserable, as she will not breach custom by going against her brother's wishes. Some time later, on the day of the Innisfree horse race, some of the locals decide to help the unhappy couple by tricking Will into giving his blessing to their courtship. They "secretly" tell Will that the widow Tillane, whom he has long admired, would gladly marry him but is reluctant because she does not want to come into a house in which another woman is living. Will soon relents and a courtship between Sean and Mary Kate begins. Although a long courtship is traditional, Sean and Mary Kate's passion, and the fact that they are no longer young, shorten the time and they are soon married. At their wedding reception, after a drunken Will shows the guests the £230 in gold coins that are part of Mary Kate's dowry, he boasts of his own impending nuptials to the widow Tillane, but she is so insulted by his brash proposal that she leaves. Enraged at the trick that has been played on him, Will throws a punch at Sean, who falls to the ground and, in a daze, momentarily recalls the tragic moment when he killed his boxing opponent. Because he has resolved never again to fight, Sean grabs Mary Kate's hand and leaves, refusing to allow her to pick up the coins that have fallen to the floor. They spend their wedding night at Sean's cottage, but Mary Kate remains so concerned about her lost money and furniture that they argue and Sean spends the night alone in a sleeping bag. The next morning, some of their friends arrive with her things, but say that Will still refuses to relinquish the money. Sean and Mary Kate still do not understand each other's ways, but in a moment of truce, decide to go to town together. After Sean refuses to ask Will for the money, Mary Kate goes to Father Lonergan and Sean goes to Playfair. Although Sean feels that Mary Kate is only interested in the money, reminding him that greed led him to be such a fierce boxer, Playfair makes him realize that in Ireland it is the custom that is important and subtly convinces Sean to fight Will to show his mettle. That night, Mary Kate and Sean tenderly reunite at the cottage and consummate their marriage. The next morning, however, when Sean awakens, Michaeleen is waiting outside the cottage to tell him that Mary Kate has left for the Dublin train. Enraged, Sean rides his horse to the station. Now resolved that he must show her and everyone that he follows the Irish ways, he summarily grabs Mary Kate off the train and drags her to the Danaher farm, followed by a rapidly swelling crowd, shouting their approval. When they arrive at the farm, Sean throws Mary Kate towards Will and demands the dowery. Cornered, Will gives Sean the money, after which a happy Mary Kate assists Sean in burning it. Now proud of Sean, Mary Kate goes to their cottage, leaving Sean and Will to resolve their animosity in a fight. As the brawling ensues, the entire village watches and wagers among themselves. Soon even neighboring villages enter into the spirit of the contest, taking sides and cheering the men on. The fight lasts so long that Will and Sean must take a break at the local pub, after which they fight again and finally stop when both are too exhausted to continue. After the fight, Sean and Will get drunk together and become friends and Mary Kate welcomes them at the cottage. The next day, as Michaeleen takes the happy Will and Tillane on a courtship outing, the entire village, including Father Lonergan, gather to cheer a visiting Anglican bishop, hoping to impress him with the size of Playfair's congregation.