In the summer of 1957, Dani Trant (Reese Witherspoon) is a 14-year-old girl in Louisiana who, according to her father, is "too big to be running off by herself." Dani and her older sister Maureen (Emily Warfield), who is going off to college in the fall, are very close. Maureen helps take care of their younger sister, Missy, while their mother Abigail (Tess Harper) is pregnant. Dani however prefers to run off to the neighbor's creek to go swimming in the nude. It is here that she meets her new neighbor, 17-year-old Court Foster (Jason London). Court kicks Dani out of his creek. When Dani goes home, her mother tells her to wash up because an old friend is coming for dinner with her children. The Trants' old friend turns out to be a widow, Mrs. Foster (Gail Strickland) with her three sons Court, Dennis, and Rob. When Dani realizes who Court is, the two dislike each other. Court calls Dani "a little girl". When Dani's father Matthew (Sam Waterston) tells Dani to accompany Court into town for groceries, Dani and Court drive into town and start to get along. Dani finally realizes that she is in love with Court.
Maureen goes on a date to a dance with her boyfriend Billy Sanders (Bentley Mitchum). When they leave the dance, Billy wants to park his car and have sex. Maureen gets angry and breaks up with Billy because she believes "love should be beautiful". The next day, Dani asks Maureen for advice on how to kiss a boy. Maureen demonstrates by practicing on her hand. Dani and Court continue to go swimming during the hot sunny days and become very close friends. The two agree to meet to go swimming at night, since Court has too much work to do during the day. Dani sneaks off and swims with Court until they reach the point where they are about to kiss. Court pushes Dani away and says she is a little girl that doesn't know what she's doing, and runs off home. Dani leaves too just as a thunderstorm is breaking out. Abigail wakes up, knowing Dani isn't home, and runs outside looking for her. Just as Dani gets home, and runs to her mother, her mother also runs and trips on a root, landing on her stomach. Dani's father races her to the hospital, where she is kept for treatment. When her father returns home from the hospital, he spanks Dani with his belt. The next day, Court brings food to the Trant house and apologizes to Dani for the other night. Dani, still hurt, just ignores him at first, until Court says he would still like to be friends. The next time they go swimming the two share Dani's first kiss. Dani is still hurt and angry at her father for hitting her. When he tries to talk to her the next day feeling remorseful for using his belt on her, she only replies with "Yes Sir" or "No Sir" to his questions.
Once Dani has made up with her father, he tells Dani to invite Court over once in a while so he can get to know him better. When Court comes over for dinner, he finally meets Maureen. Dani can tell it is love at first sight for the two of them. While Dani visits her mother in the hospital, Court comes over to the Trant house and kisses Maureen. Over the next few days, Dani is getting pushed away by Court. While the rest of the family goes to pick up Abigail and the new baby from the hospital, Court and Maureen claim their love for each other, consummating their love in a field. When Maureen leaves for home, Court goes back to plowing the fields and falls off the tractor, and is badly injured. Dani sees this, and races home to tell her father. When Matthew returns home, he has some of Court's blood on his clothes and the family realizes that Court has died. Maureen hides her pain at first, while Dani bursts into tears. After Court's funeral, Dani continues to be angry at Maureen for stealing Court away from her. Matthew tells Dani that although she has a right to be hurt, being mad won't bring Court back, and Maureen will be her sister for life. Dani comforts Maureen as she weeps on Court's fresh grave, and the film ends with Maureen and Dani talking outside on the porch at night as the summer draws to a close, looking up at the moon becoming close again.Sam Waterston as Matthew Trant
Tess Harper as Abigail Trant
Gail Strickland as Marie Foster
Reese Witherspoon as Dani Trant
Jason London as Court Foster
Emily Warfield as Maureen Trant
Bentley Mitchum as Billy Sanders
Ernie Lively as Will Sanders
Dennis Letts as Doc White
Earleen Bergeron as Eileen Sanders
Anna Chappell as Mrs. Taylor
Brandi and Sandi Smith as Missy Trant
Derek and Spencer Ball as Foster Twins
The Man in the Moon marked the film debut of Reese Witherspoon at the age of 14 years. Director Mulligan commented that casting her in the role of Dani was “risky business, to say the least. We had a casting team that went out and saw several thousand kids and tested them on video. When I saw Reese’s test, she just jumped off the screen, simply as a personality. I couldn’t tell whether she could act or not, but she’s got a wonderful face and there’s a brightness and intelligence there. Then, when I tested her in Santa Monica, a strange breakthrough took place. Early in the movie, Dani is a bit of a tomboy. Reese was trying to project this in a scene where she had to get angry with the boy, but it had a false ring to it. Because in real life she isn’t a tomboy. She’s a real ‘girl’ girl. Just before we did another rehearsal, I told her I wanted her to chew gum. Well, she started chewing gum and all of a sudden the performance happened. She was tough. Strong. Direct. And the scene worked. Like that. In an instant, it was there. What was marvelous was, at the end of the scene, Reese knew that something happened. Her compass, her sense of what’s real, kicked in. The motor was running and she knew it. It was funny because she said: ‘Can I always chew gum?’ And I said: ‘Yeah.’” The photography was by Academy Award-winning cinematographer Freddie Francis.
The film was highly praised by Roger Ebert, who included it at No. 8 in his Top 10 list of the best films of 1991, declaring, "Nothing else [Mulligan] has done... approaches the purity and perfection of The Man in the Moon. As the film approached its conclusion without having stepped wrong once, I wondered whether he could do it - whether he could maintain the poetic, bittersweet tone, and avoid the sentimentalism and cheap emotion that could have destroyed this story. Would he maintain the integrity of this material? He would, and he does."
Later, Mulligan became disenchanted with how the film was edited and cut by airlines, particularly American and Delta Air Lines, for in-flight showings. He became so disturbed by these airline edits to the picture that he insisted that his name be removed from the credits of the film.