High school senior Daniel LaRusso and his mother move from Newark, New Jersey to Reseda, Los Angeles, California. Their maintenance man is an eccentric, kind and humble Okinawan immigrant named Kesuke Miyagi.
At a beach party, Daniel meets Ali Mills, a high school cheerleader from Encino. Johnny Lawrence, Ali's ex-boyfriend, is the top student of a karate dojo called "Cobra Kai," who breaks Ali's radio in a fit of anger. Daniel attempts to intervene but is easily overpowered and humiliated by the better-trained Johnny. Johnny and his gang bully, bother, and harass Daniel. They start by provoking a fight that gets Daniel thrown out of the soccer team, then causing Daniel to crash on the street and wrecking his bicycle, which Miyagi subsequently repairs. At a Halloween party, Daniel douses Johnny with water, leading to a chase. Daniel is caught by Johnny and his accomplices and beaten savagely. Mr. Miyagi rescues him and defeats the five attackers with ease.
Daniel asks Miyagi to teach him to fight. Miyagi refuses, instead agreeing to accompany Daniel to the Cobra Kai dojo to resolve the conflict. They meet with the sensei, John Kreese, an ex-Special Forces Vietnam veteran, who teaches his students to be aggressive and merciless against their opponents. He dismisses the peace offering made by Miyagi and demands to set up a match between Daniel and the other Cobra Kai students. Miyagi proposes that Daniel will enter the Under-18 All-Valley Karate Tournament, where he can compete with all the Cobra Kai students, and he requests that the bullying cease while Daniel trains. Kreese agrees to the terms, and warns that if Daniel does not appear at the tournament, the harassment will resume on Daniel and Miyagi.
Miyagi begins Daniel's training by telling him that Daniel is required to commit unequivocally to Miyagi's curriculum, and to obey Miyagi's every instruction, without question. After Daniel agrees, Miyagi assigns Daniel to complete various lengthy, menial chores that appear to have nothing to do with karate. Daniel, perplexed, obeys. By the end of the fourth task, Daniel becomes frustrated, angry that Miyagi is apparently exploiting him for menial labor. When Miyagi attacks Daniel, he defends himself due to muscle memory from the tasks. Their bond develops, and as their training continues, Daniel learns about Miyagi's dual loss of his wife and newborn son due to complications arising from childbirth at Manzanar internment camp while he was serving with the 442nd Infantry Regiment during World War II in Europe, where he received the Medal of Valor. Through Miyagi's teaching, Daniel learns important life lessons such as the importance of personal balance, reflected in the principle that martial arts training is as much about training the spirit as the body. Daniel applies the life lessons that Miyagi has taught him to strengthen his relationship with Ali.
At the tournament, Daniel unexpectedly reaches the semi-finals. After Johnny defeats a highly skilled opponent, Kreese becomes worried that Daniel might make it to the finals and defeat Johnny. Accordingly, he instructs Bobby Brown, one of his more compassionate students and the least vicious of Daniel's tormentors, to disable Daniel with an illegal attack to the knee. Bobby reluctantly does so, getting disqualified in the process. Before he is forced out, Bobby apologizes to Daniel. Daniel is taken to the locker room, where the physician determines that he cannot continue, and Miyagi agrees. Daniel thinks the tormentors will have won, so he convinces Miyagi to use a pain suppression technique so that he can continue. As Johnny is about to be declared the winner by default, Ali tells the master of ceremonies that Daniel will fight. Daniel hobbles into the ring and faces Johnny.
The match is halted when Daniel uses a scissor leg technique to trip Johnny and deliver a blow to the back of the head, giving him a nose bleed. Kreese orders Johnny to sweep Daniel's injured leg, an unethical move. Johnny at first horrified by the order, obeys under Kreese's intimidation. As the match continues, Johnny seizes Daniel's leg and delivers a vicious blow, doing further damage. Daniel, standing with difficulty, assumes the crane stance, a technique he observed Miyagi performing on the beach. Johnny lunges toward Daniel, who jumps and delivers a kick to Johnny's chin, winning the tournament. Having gained respect toward his nemesis, Johnny presents Daniel's trophy to Daniel himself as Daniel is carried off by the enthusiastic crowd.
The production obtained permission from DC Comics to use Karate Kid as the title of their film.
According to the special-edition DVD commentary, the studio originally wanted the role of Mr. Miyagi to be played by Toshiro Mifune, but writer Robert Mark Kamen was opposed to that casting choice feeling that Mifune's interpretation of the character lacked the warmth and humor that the role needed. Mako was also considered for the role of Mr. Miyagi, but was not available due to prior commitments to film Conan the Destroyer, though he would eventually play a similar role in the film Sidekicks. According to Randee Heller, two days after she was cast, Jerry Weintraub informed her that they intended to replace her with Valerie Harper. John G. Avildsen said that after seeing Harper's audition they decided not to replace Heller after all.
Filming began on October 31, 1983, and wrapped on December 16, 1983.
The musical score for The Karate Kid was composed by Bill Conti, a frequent collaborator of director John G. Avildsen since their initial pairing on Rocky (1976). The instrumental score was orchestrated by Jack Eskew and featured pan flute solos by Gheorge Zamfir. On March 12, 2007, Varèse Sarabande released all four Karate Kid scores in a 4-CD box set limited to 2,500 copies worldwide.
A soundtrack album was released in 1984 by Casablanca Records containing many of the contemporary songs featured in the film. Of particular note is Joe Esposito's "You're the Best", featured during the tournament montage near the end of the first film. Originally written for Rocky III, "You're the Best" was rejected by Sylvester Stallone in favor of Survivor's "Eye of the Tiger". Coincidentally, Survivor also performed the main theme ("The Moment of Truth" Music & Lyrics: Bill Conti, Dennis Lambert, Peter Beckett) for The Karate Kid.
Bananarama's 1984 hit song "Cruel Summer" also made its U.S. debut in The Karate Kid but was excluded from the film's soundtrack album. Other songs featured in the film but left off the album include "Please Answer Me" performed by Broken Edge and "The Ride" performed by The Matches.Track listing for 1984 soundtrack
- "The Moment of Truth" (Survivor)
- "(Bop Bop) On the Beach" (The Flirts, Jan & Dean)
- "No Shelter" (Broken Edge)
- "Young Hearts" (Commuter)
- "(It Takes) Two to Tango" (Paul Davis)
- "Tough Love" (Shandi)
- "Rhythm Man" (St. Regis)
- "Feel the Night" (Baxter Robertson)
- "Desire" (Gang of Four)
- "You're the Best" (Joe Esposito)
The Karate Kid ranked #40 on Entertainment Weekly's list of the 50 Best High School Movies.
On its release, Roger Ebert called the film one of the year's best, gave it four stars out of four, and described it as an "exciting, sweet-tempered, heart-warming story with one of the most interesting friendships in a long time." Janet Maslin of The New York Times also gave a positive review.
Upon release of the 2010 remake, Dana Stevens wrote, "The 1984 original ... may have seemed like a standard-issue inspirational sports picture at the time, but (as with another box-office hit of the same year, The Terminator) a generation of remove reveals what a well-crafted movie it actually was. Rewatched today, the original Kid, directed by Rocky's John G. Avildsen, feels smart and fresh, with a wealth of small character details and a leisurely middle section that explores the boy's developing respect for his teacher."
The film spawned a franchise of related items and memorabilia such as action figures, head bands, posters, T-shirts, and a video game. A novelization was made by B.B. Hiller and published in 1984. The novel had a scene that was in the rehearsal when Daniel encounters Johnny during school at lunch. Also at the end, there was a battle between Miyagi and Kreese in the parking lot after the tournament which was the original ending for the film and used as the beginning of The Karate Kid Part II.
A short-lived animated series spin-off aired on NBC in 1989.
The music video for the song "Sweep the Leg" by No More Kings stars William Zabka (who also directed the video) as a caricature of himself and features references to The Karate Kid, including cameo appearances by Zabka's former Karate Kid co-stars.
In 2015, toy company Funko revived The Karate Kid action figures. Two versions of character Daniel Larusso, a version of character Johnny Lawrence and a version of Mr. Miyagi were part of the line. The toys were spotted at retailers Target and Amazon.com.
The original 1984 film had three sequels, and it launched the career of Macchio, who would turn into a teen idol featured on the covers of magazines such as Tiger Beat. It revitalized the acting career of Morita, previously known mostly for his comedic role as Arnold on Happy Days, who was nominated for a Best Supporting Actor Academy Award for his performance as Mr. Miyagi. Morita reprised his role in three subsequent sequels.The Karate Kid Part II: A 1986 sequel in which Daniel accompanies Miyagi on a trip back to Okinawa (Japan), where he is reunited with loved ones, and is challenged by an old adversary.
The Karate Kid Part III: A 1989 sequel in which Kove reappears as Kreese, seeking revenge on Daniel and Miyagi with the help of allies played by Thomas Ian Griffith and Sean Kanan.
The Next Karate Kid: A 1994 revamp sequel in which Hilary Swank appears as Mr. Miyagi's new student, Julie Pierce.
The Karate Kid: A 2010 remake starring Jackie Chan and Jaden Smith.
On August 4, 2017, it was announced that a new TV series was in development to continue the Karate Kid franchise. The series titled Cobra Kai will reunite Ralph Macchio and William Zabka who are set to reprise their roles as Daniel LaRusso and Johnny Lawrence respectively. The half-hour comedy will be set 34 years after the original film, focusing on Johnny who is down on his luck and re-opens the Cobra Kai dojo on his search for redemption. This puts him at odds with Daniel, who, though successful, is trying to find balance in his life without Mr. Miyagi.
Josh Heald will write the script with Jon Hurwitz and Hayden Schlossberg while the latter duo will direct most of the series, they will also executive-produce alongside Macchio and Zabka. The series received an order of 10 episodes for the first season which is set to debut on YouTube Red in 2018.