Since its release, Home Alone has become the highest-grossing live action comedy film of all time in the US and was as well worldwide until The Hangover Part II in 2011. Home Alone has spawned a successful film franchise with four sequels, including the 1992 film Home Alone 2: Lost in New York, the only Home Alone sequel to have the original cast reprising their roles.
In the Chicago suburb of Winnetka, Illinois, the McCallister family is preparing for a Christmas vacation in Paris. On the night before their departure, the entire family gathers at Peter and Kate's home, where their 8-year-old son, Kevin, is ridiculed by his siblings and cousins. After an argument with his older brother, Buzz, Kevin is sent to the third floor of the house, where he wishes that his family would disappear. During the night, heavy winds cause damage to power lines, which causes the alarm clocks to reset; consequently, the family oversleeps. In the confusion and rush to get to the airport in time to catch their flight, Kevin is accidentally left behind.
Meanwhile, Kevin wakes up to find the house empty and, believing his wish has come true, is overjoyed with his new-found freedom. However, Kevin's joy turns to fear as he encounters his next door neighbor, "Old Man" Marley, who is rumored to have murdered his family with a snow shovel in 1958; and the "Wet Bandits," Harry and Marv, a pair of burglars who have been breaking into other vacant houses in the neighborhood and have targeted the McCallister's house. Kevin is initially able to keep them away by making the house appear as if the family is at home, but they realize after three failed attempts that Kevin is home alone.
Kate realizes mid-flight that Kevin is missing and, upon arrival in Paris, the family finds out all flights to Chicago for the next 2 days are completely sold out. Peter and the rest of the family go to his brother Rob's apartment in the city while Kate manages to get a flight back to the United States but is only able to get as far as Scranton, Pennsylvania. She tries to book a flight to Chicago but again, there are no seats left. Unable to accept this, Kate is overheard by Gus Polinski, the lead member of a traveling polka band, who offers to let her travel with them to Winnetka on their way to Milwaukee in a moving van, which she happily accepts.
On Christmas Eve, Kevin overhears Harry and Marv discussing plans for breaking into his house that night. Kevin goes to church and watches a choir perform. He runs into Marley, who sits with Kevin and they briefly speak; he learns that Marley is actually a nice man and that the rumors about him are false. He tells Kevin he is watching the choir because his granddaughter is in it, but he never gets to see her because he and his son are estranged, and have not been on speaking terms ever since; Kevin suggests that he try to reconcile with his son.
Kevin returns home and rigs the house with numerous booby traps. Harry and Marv break in, springing the traps and suffering various injuries. While the duo chases Kevin around the house, he calls the police and escapes the house, luring the duo into a neighboring vacant home. Harry and Marv manage to catch him and discuss how they will get their revenge, but Marley sneaks in and knocks them unconscious with his snow shovel before they can do anything to Kevin. The police arrive and arrest Harry and Marv, having identified all the houses they burglarized due to Marv's habit of flooding them.
On Christmas Day, Kevin is disappointed to find that his family is still gone. He then hears Kate enter the house and call for him; they reconcile and are soon joined by the rest of the McCallisters, who waited in Paris until they could get a direct flight to Chicago. Kevin keeps silent about his encounter with Harry and Marv, although Peter finds Harry's missing gold tooth. Kevin then observes Marley reuniting with his son and his family. Marley notices Kevin and the pair acknowledge each other before Marley and his family go home. Buzz suddenly calls out, "Kevin, what did you do to my room?!" at which point Kevin runs off.
Macaulay Culkin as Kevin McCallister, an energetic 8-year-old boy who is the youngest son of the McCallister family. He can be obnoxious and annoying, but he is proven to be extremely clever and resourceful.
Joe Pesci as Harry, the short leader of the Wet Bandits. He is intelligent but short tempered and ruthless.
Daniel Stern as Marv, the tall member of the Wet Bandits. The dimmer of the duo, he has a childlike enthusiasm for toys and likes to leave the water running to 'mark' the houses they have robbed.
John Heard as Peter McCallister, Kevin's father.
Catherine O'Hara as Kate McCallister, Kevin's mother.
Roberts Blossom as Old Man Marley, the McCallisters' elderly neighbor.
The rest of the McCallister family is portrayed by: Devin Ratray as Buzz and Mike Maronna as Jeff, Kevin's brothers; Hillary Wolf as Megan and Angela Goethals as Linnie, Kevin's sisters; Gerry Bamman as Uncle Frank; Terrie Snell as Aunt Leslie; and Kevin's cousins are portrayed by Jedidiah Cohen as Rod, Senta Moses as Tracy, Daiana Campeanu as Sondra, Kieran Culkin as Fuller, Anna Slotky as Brooke, and Kristin Minter as Heather.
The cast also includes: John Candy as Gus Polinski, "the Polka King of the Midwest"; Ralph Foody as Johnny, a gangster who appears in the fictional film Angels with Filthy Souls; Larry Hankin as Larry Balzak, a police sergeant who works in family crisis; Ken Hudson Campbell as a man dressed as Santa Claus; and Hope Davis as a Paris-Orly Airport receptionist.