| Character | Actor | Description |
| Kumiko Tanaka | Tamlyn Tomita | Briefly has a relationship with Daniel during his visit to Okinawa. She and Daniel meet again a few decades later in Cobra Kai season 3, after she has become a professional dancer who once toured with a dance company. During this visit to Okinawa, she helps Daniel and Chozen resolve their decades-long rivalry, and reunites Daniel with Yuna. In Cobra Kai season 5, Chozen calls Kumiko leaving her a message that he is in love with her. In Cobra Kai season 6, she writes Chozen a letter saying she loves him as a friend only and she is in love with someone else. |
| Chozen Toguchi | Yuji Okumoto, Shigi Ohtsu | The main antagonist for The Karate Kid Part II, and Daniel's rival. Chozen is Sato's nephew, and the top student of his dojo. He and Daniel meet again a few decades later in Cobra Kai season 3, where Chozen is now the sensei of Miyagi-Do in Okinawa. After Kumiko helps them resolve their differences and become friends, Chozen helps Daniel in his feud in Cobra Kai season 5 and Cobra Kai season 6. In season 5, he confesses his love for Kumiko and calls leaving her a message. In season 6, she writes him a letter telling him she loves him as a friend only and she's in love with someone else, leaving Chozen heartbroken; however, he eventually finds love, and starts dating former rival-turned-friend Kim Da-eun, who is now reformed. |
| Sato Toguchi | Danny Kamekona, Akihiro Kitamura | Chozen's uncle and Mr. Miyagi's former best friend. He was arranged to marry Yukie, but she had already fallen in love with Miyagi. In 1972, when he is training a young Chozen and American soldiers, he catches Chozen cheating and scolds and yells at Chozen, reducing Chozen to tears. Sato and Mr. Miyagi end up becoming friends again after Mr. Miyagi saves his life during the typhoon. In Cobra Kai season 3, it was revealed that before he died, he matured, was respectful towards Mr. Miyagi, made Tomi Village a tourist attraction and reformed Chozen. |
| Yukie | Nobu McCarthy | Mr. Miyagi's childhood girlfriend and Kumiko's aunt. Yukie and Sato were planned to marry each other, but Yukie in actuality loves Miyagi. This led to a death match between Sato and Miyagi, in which Miyagi decided to forfeit. In the third season of Cobra Kai, it is revealed that Yukie died and Kumiko had inherited her property. |
| Yuna | Traci Toguchi | A little girl who is nameless in the film and who lives at Tomi Village. Daniel rescues her from the bell tower during a typhoon. A few decades later in Cobra Kai season 3, she appears as Yuna, the senior vice president of sales for Doyona International, who speaks perfect English and saves Daniel's business. |
| Autograph Fan #1 | Garth Johnson | Two young boys who ask Daniel for his autograph after Daniel won the Tournament. They tell Daniel they are from Reseda, making Daniel happy and he tells them he is from their too. |
| Autograph Fan #2 | Brett Johnson | Two young boys who ask Daniel for his autograph after Daniel won the Tournament. They tell Daniel they are from Reseda, making Daniel happy and he tells them he is from their too. |
| Toshio | Joey Miyashima | Chozen's friends who helped to torment Daniel. |
| Taro | Marc Hayashi | Chozen's friends who helped to torment Daniel. |
| Miyagi Chōjun | Charlie Tanimoto | Miyagi's father; trained both Miyagi and Sato. He is dying due to his old age and Miyagi returns to Okinawa to see his dad in his final days. His final wish was for Miyagi and Sato to become close friends again and make peace, then he passes away in front of a saddened Miyagi, Sato, Daniel, Yukie, and Kumiko. The next day, his funeral is held with Miyagi, Daniel, Sato, Yukie, Kumiko and the Tomi Village residents in attendance. |
| Ichiro | Arsenio "Sonny" Trinidad | Old villager that lives in Tomi Village; witness to Daniel's first confrontation with Chozen when Chozen is exposed as a fraud. |
| Village Woman | Tsuruko Ohye | A villager who says hello to Mr. Miyagi and Mr. Miyagi tells Daniel that he remembers her from school. |
| Okinawan Boy | BD Wong | A friend of Kumiko's who tells her about a dance and suggests she invites Daniel to the dance. |
| G.I. Soldier | Clarence Gilyard | An American soldier on vacation in Okinawa who makes a bet on Daniel to break all six ice blocks. |
| Character | Actor | Description |
| Terry Silver | Thomas Ian Griffith, Nick Marini | The main antagonist of The Karate Kid Part III, and one of the two main antagonists of Cobra Kai. Co-founded Cobra Kai with John Kreese, a war comrade and friend of his. He takes over the Cobra Kai dojo completely in the season 4 finale of Cobra Kai, and runs it throughout all of season 5 until he is defeated by the protagonists in the season finale. Afterwards, he becomes the manager of the Iron Dragons in season 6, hoping to get revenge on both Miyagi-Do and Cobra Kai. He attempts to kidnap Carmen and her daughter, but is blown up by Kreese in his yacht explosion. |
| Mike Barnes | Sean Kanan | The secondary antagonist of The Karate Kid Part III. Returns in Cobra Kai season 5 as a furniture store owner which is co-owned by him and his wife; the furniture store gets burned down by his former ally, Dennis, who is still working for Terry Silver. He eventually becomes an ally of Daniel, Chozen, and Johnny in both season 5 and Cobra Kai season 6. |
| Jessica Andrews | Robyn Lively | Came to work in her Aunt Pat's pottery shop after Elizabeth-Anne Rooney ruined her relationship; spent time with Daniel LaRusso, but they decided to just be friends. Appeared in Cobra Kai season 5 as Amanda's maternal cousin. |
| Snake | Jonathan Avildsen | One of Silver's henchmen who, along with Mike and Dennis, torments Daniel throughout The Karate Kid Part III. It is later revealed that he died some time before the events of Cobra Kai season 6. |
| Dennis de Guzman | William Christopher Ford | One of Silver's henchmen who, along with Snake and Mike, torments Daniel throughout The Karate Kid Part III. He later returns as a major antagonist in Cobra Kai season 6, where he once again works with Terry Silver, who at this point has become the manager of the Iron Dragons. He was later revealed to be the one who burned down the furniture store that was owned by his former ally, Mike Barnes. He's killed by John Kreese in the penultimate episode when Kreese snaps his neck before blowing up Silver's yacht in order to stop him from going after Johnny's family. |
| Uncle Louie | Joseph V. Perry | Daniel's uncle and Lucille's brother-in-law; becomes ill. Is revealed to be the father of Louie Jr. and Vanessa in Cobra Kai. |
| Milos Dadok | Jan Tříska | Terry Silver's Czech butler. |
| Margaret Spencer | Diana Webster | Terry Silver's English secretary. |
| The Announcer | Rick Hurst | Announcer of the All Valley Under-18 Karate Championships tournament in The Karate Kid Part III. |
| Rudy | Gabriel Jarret | A teenager at the downstairs dance club that Daniel and Jessica attend, and also attended by Terry. Terry secretly bribes Rudy to hit on Jessica and when he does, she rejects him while Daniel punches him in the face giving him a broken nose; Jessica storms off disgusted by Daniel's behaviour and Terry and Daniel flee the club, while bouncers remove Rudy from the club who complains about Terry not giving him his money as promised. |
| Glenn Medeiros | Himself | American singer performing at a downstairs dance club that Daniel and Jessica attend. |
| Character | Actor | Description |
| Julie Pierce | Hilary Swank | Protagonist of The Next Karate Kid. Teenage girl who lost her parents, Susan and her unnamed father, now living with her paternal grandmother Louisa Pierce. As she is a frequent victim of bullying, Mr. Miyagi teaches her Karate to defend herself. She helps heal a female Hawk with a broken leg who she names Angel and when Julie goes to the monastery with Mr. Miyagi, she has Eric McGowen, her love interest, look after Angel; when Angel is fully recovered, she and Mr. Miyagi release Angel back into the wild. She attends prom with Eric, and later that night fights Ned, her bully, and manages to defeat him.
Throughout Cobra Kai's run, there was speculation that Swank might reprise the role of Julie. According to Heald, they had a storyline involving Julie related to Mr. Miyagi and the mystery of a stolen necklace for Cobra Kai season 6, "but before we got too deep, we had to reach out to Hilary and find out would she be willing to come and play with us." At the end of the series in 2025, the creators stated that Swank would not appear as, "people have all sorts of reasons why they will or will not be participating in something, and with the timing of whatever was going on, it just was never an option." However, they also indicated that they will "have to see what might happen in this universe if we're fortunate enough to continue writing within it. She's a character that we have a lot of excitement to revisit." |
| Lieutenant Jack Pierce | NA | Julie's late grandfather, husband of Louisa Pierce, father of Julie's unnamed father, and Mr. Miyagi's military commander during World War II; both were in the 442nd Infantry Regiment. Mr. Miyagi eventually taught Jack Pierce Karate as a message of thanks for saving his life. Pierce would eventually teach Karate to his son, who taught it to Julie. |
| Louisa Pierce | Constance Towers | Julie's grandmother, widow of Jack Pierce, mother of Julie's unnamed father. Mr. Miyagi sends her to Los Angeles to his home in order to give him time to bond with Julie, and help her cope with bullying, as well as the loss of her parents. |
| Colonel Dugan | Michael Ironside | Main antagonist of The Next Karate Kid. Leads a JROTC-style program, Alpha Elite, at Julie's school. After losing a fight to Mr. Miyagi, his students quit on him. |
| Eric McGowen | Chris Conrad | New student who joins Alpha Elite to someday be accepted into the Air Force Academy; Julie's love interest. He later quits Alpha Elite, not approving of Col. Dugan's training methods. Eric takes Julie to prom. Later that night he fights Ned, but gets defeated by him, so Julie steps in and manages to defeat Ned. |
| Ned | Michael Cavalieri | Secondary antagonist of The Next Karate Kid. Skilled academy student and gang leader of the Alpha Elite; fought Eric and Julie, with the latter defeating him; he then quits Alpha Elite due to Col. Dugan's abuse and losing his fight to Mr. Miyagi. |
| Charlie | Walton Goggins | Ned's friends; students of the Alpha Elite who later quit due to Col. Dugan's abuse. |
| Gabe | Tom O'Brien | Ned's friends; students of the Alpha Elite who later quit due to Col. Dugan's abuse. |
| Morgan | Thomas Downey | Ned's friends; students of the Alpha Elite who later quit due to Col. Dugan's abuse. |
| Abbot | Arsenio "Sonny" Trinidad | The monks. Abbot is the lead monk of the monastery. They are old friends with Mr. Miyagi. They briefly shun Julie when she tries to kill a cockroach as it goes against their beliefs in killing wildlife, but make amends with her when she gifts them with a praying mantis, and befriend her, and celebrate her birthday. They later visit Julie and Mr. Miyagi at Julie's grandmother's home and when Julie attends prom, Mr. Miyagi and the Monks go bowling where they do zen bowling, impressing the crowd at the bowling alley. |
| Tall Monk | Jim Ishida | The monks. Abbot is the lead monk of the monastery. They are old friends with Mr. Miyagi. They briefly shun Julie when she tries to kill a cockroach as it goes against their beliefs in killing wildlife, but make amends with her when she gifts them with a praying mantis, and befriend her, and celebrate her birthday. They later visit Julie and Mr. Miyagi at Julie's grandmother's home and when Julie attends prom, Mr. Miyagi and the Monks go bowling where they do zen bowling, impressing the crowd at the bowling alley. |
| Monk | Rodney Kageyama | The monks. Abbot is the lead monk of the monastery. They are old friends with Mr. Miyagi. They briefly shun Julie when she tries to kill a cockroach as it goes against their beliefs in killing wildlife, but make amends with her when she gifts them with a praying mantis, and befriend her, and celebrate her birthday. They later visit Julie and Mr. Miyagi at Julie's grandmother's home and when Julie attends prom, Mr. Miyagi and the Monks go bowling where they do zen bowling, impressing the crowd at the bowling alley. |
| Buddhist Monk | Seth Sakai | The monks. Abbot is the lead monk of the monastery. They are old friends with Mr. Miyagi. They briefly shun Julie when she tries to kill a cockroach as it goes against their beliefs in killing wildlife, but make amends with her when she gifts them with a praying mantis, and befriend her, and celebrate her birthday. They later visit Julie and Mr. Miyagi at Julie's grandmother's home and when Julie attends prom, Mr. Miyagi and the Monks go bowling where they do zen bowling, impressing the crowd at the bowling alley. |
| Senator Daniel Inouye | Himself | Made a cameo giving the opening speech at Arlington National Cemetery for a commendation for Japanese-Americans who fought in the 442nd Regimental Combat Team during World War II. |
| Girl At Prom | Julie Weintraub | A girl attending prom who alerts everyone at the prom about the Alpha Elite bungee jumping in the gym. She's portrayed by the daughter of the late producer Jerry Weintraub, who produced The Karate Kid films. |