At first, Thunderbolt is arrogant and selfish, seeming to only care about his job and his popularity. He is very popular with other dogs, all the ladies love him, and Patch is his biggest fan, knowing all of the episodes of his show by heart. As the film goes on, Thunderbolt becomes more kind and helpful, and he and Patch start to become friends. Furthermore, he is willing to assist those in need and is not afraid to admit he is just an actor and all of his amazing heroics on his show are fake. He is also cunning and highly skilled with his acting as seen when he tricks Cruella De Vil, Jasper, Horace, and Lil' Lightning into thinking he is having a heart attack.
Thunderbolt is the Dalmatian pups' favorite TV show hero. In the show, he is shown to be chasing Dirty Dawson, with the horse thief shooting at him. Dawson then travels on foot as Thunderbolt searches. In some scenes, it shows Thunderbolt making a leap across a canyon before it seems like Dawson has shot Thunderbolt. However, Thunderbolt is only pretending and as Dawson laughs about this, Thunderbolt then attacks. The two fall into a river, having the show end in a cliffhanger as they are about to fall down a waterfall.
In the show, Thunderbolt is joined by his offbeat sidekick Lil' Lightning fight to defeat Dirty Dawson.
In an episode, Dirty Dawson kidnaps a helpless boy named Tommy. It is up to Thunderbolt and Lil' Lightning to defeat him before any harm befalls Tommy. As Dawson ties Tommy to a moving train, Thunderbolt perches on a cliff. He jumps to the train, confronting Dawson. Whilst Thunderbolt fights Dawson, Lil' Lightning unties Tommy. Dawson causes Thunderbolt to stumble between the train carts and as he is about to strike Thunderbolt, another train heads by the train carts they are on, allowing Thunderbolt to get around Dawson. Thunderbolt then tangles Dawson in his own whip, tripping him up and making him fall into a boxcar with a mad bull. Tommy is then rescued and Thunderbolt saves the day.
While watching The Thunderbolt Adv'enture Hour, Patch, longing to feel one-of-a-kind like his hero Thunderbolt, hears about a chance to appear on the show while it is filming in London. However, when Roger, Anita, and the 101 Dalmatians plan to move to the Dalmatian Plantation, the family move will interfere with Patch's opportunity – until he is accidentally left behind in the commotion. Patch heads for the audition to meet his hero. Meanwhile, Lil' Lightning tells Thunderbolt the producers want to replace him with a younger dog.
In order to save his job, Thunderbolt decides to go into the real world and perform an act of true heroism to prove himself. A veritable reference book to Thunderbolt's many adventures, Patch provides the perfect guide for Thunderbolt in his attempts at real-life heroics.
Later, after many unsuccessful attempts at gaining the attention of the London photographers, Thunderbolt prepares to tell Patch the truth about himself, but is interupted when Patch hears info of the twilight bark that his siblings have been kidnapped by Cruella again and then asks Thunderbolt to help him and his family. Thunderbolt attempts to tell Patch the truth again, but when Patch snuggles against him, he kindly agrees and gives a big bark across the entire city informing all dogs he's on the way. When Thunderbolt and Patch arrive at the warehouse Patch's siblings are being held, Lightnight meets them there, saying he thought they could use a bit of help and Thunderbolt kindly thanks him. Thunderbolt jumps up and pulls down the bottom part of a stairwell to climb onto the roof then enter the warehouse through an open roof window with Patch and Lightning. Once inside, Thunderbolt gives a loud bark catching the attention of everyone inside. The puppies then become very excited, believing Thunderbolt will save them, but Cruella gives Thunderbolt a big hit in the head with a paint can, knocking him unconscious. He and Patch are then locked in a cage crate. When Thunderbolt regains consciousness, Patch excitedly claims he knew he was faking it and Lightning replies that "he's been faking it alright". Thunderbolt is happy to see his "little buddy" at first, but Lightning reveals that he is not his little buddy and he is no wonder dog. Lightning then explains to Patch that Thunderbolt has been lying to him all day, doesn't care about him or his family and only wants to get his name in the newspaper and save his job and then tells Patch to ask him. Thunderbolt is confused on what to say and Lightning then yells to him that he's no hero, he's a fraud, and that he just wanted to get him out of the way so he can steal his place on the show and then leaves through the roof window, laughing wickedly. A confused Patch then asks Thunderbolt what Lightning meant by everything he just explained. Thunderbolt finally explains the truth that he's really just an actor and all the amazing heroic stuff on his show is make-believe. A sad and disappointed Patch cries out that he promised he'd help them, but all Thunderbolt can do is apologize because he's not a real wonder dog.
Later that night, while talking with Lucky, Patch is reminded of an episode where Thunderbolt got out of a cage himself, does what he saw on TV, and successfully breaks out of his cage much to his family's joy. Jasper hears the puppies bark, but only tells them to stop barking because he's trying to sleep at the same time Horace is asleep snoring loudly. Patch then opens all of the cages his siblings are confined in and they all hide, but the disappointed Thunderbolt decides to stay in his open cage. After Patch escapes the warehouse through the open roof window while evading Cruella, Jasper, and Horace, Thunderbolt looks up at him and smiles with some amazement upon seeing he is starting to prove himself to be a real hero. He watches Cruella, Jasper, and Horace head downstairs in the elevator then leaves his cage to see Lars still tied up and the two give each other a slightly confused eye look.
During, the road chase between the puppies and Cruella, Jasper, and Horace, Thunderbolt frees Lars and Lars then takes him to the alley Cruella, Jasper, and Horace have the puppies cornered in to help Patch stop them. Patch is initially confused based on what he learned about Thunderbolt earlier, but Thunderbolt recalls that he always arrives just in the nick of time like on his show. He claims that he may not be a real hero, but he can act like one. He then gives another big bark before Jasper prepares to hit him with a long piece of metal which appears to make Thunderbolt panic and he tells Lightning to not let them hurt him. Thunderbolt fakes a heart attack wobbling around and manages to get Cruella to accidentally hit Jasper and Horace knocking them both unconscious and spin herself around resulting in her falling into a trashcan. He then pretends to die and Lightning cries over this, but when Patch starts the bus up again, making it back up, Thunderbolt jumps back up, licks Lightning, runs through the bus with Patch and the two make their way out of the front through the broken windshield. As the bus drives back Lightning, Cruella, Jasper, and Horace start running for their lives from it and as they make their way out of the alley the bus crashes into the kanine krunchies truck sending it driving back after them forcing them all to jump into the Thames River while the truck falls in after them and sinks. While the four are drowning the sun shines on Thunderbolt and Patch as they both let out loud heroic barks. Shortly after, lots of police arrive whom Lars and Nanny explain things to. Lightning is taken away by two police dogs while Jasper and Horae explain that Cruella forced them to steal the puppies for her and she is taken away by the mental institute. Roger, Anita, Pongo, and Perdita then arrive happy to be reunited with the puppies especially Patch who introduces his parents to Thunderbolt saying he saved them. Pongo thanks him greatly for saving his family, but Thunderbolt tells him not to thank him because it was really Patch who did the great heroics. The rest of the puppies then explain then Patch did fantastic heroics just like Thunderbolt. Thunderbolt then proudly tells Patch they're right and explains that he's really just an actor, but Patch is a "real one-of-a-kind Wonder Dog". Many photographers then show up for a big picture and Thunderbolt lifts Patch onto his head for it and they along with the entire Dalmatian family have their picture taken which ends up in the newspaper along with their great story.
A post-credits scene shows Thunderbolt with Patch in his TV show The Thunderbolt Adventure Hour.
In 101 Dalmatians: The Series, Thunderbolt is the star of a show titled Thunderbolt P. I., where he works with a James Bond-like partner named Rex Hunter. There are also a number of villains in the said show, such as Bone Daddy, Doctor Wonko, the Masked Marauders, and even his evil twin.
Thunderbolt also appears in "Kanine Krunchies" advertisements (including the one from the original film) and even stars in his own film.
Thunderbolt made a physical appearance in "Watch for Falling Idols", where he and his creators arrive on the Dearly Farm to film their next episode. Lucky is thrilled to meet his idol and tells Thunderbolt he is his biggest fan and that they once met at the Gruteley County Fair, where Thunderbolt supposedly autographed a picture. Lucky also claims to have seen all of Thunderbolt's movies. Before the episode is filmed, Thunderbolt is seen relaxing in a hot tub inside his trailer, where he is idolized by Lucky, who even waits on him. However, when Lucky later finds out that Thunderbolt doesn't do his own stunts (after Thunderbolt panics from being lifted off the ground, due to his fear of heights), he shuns Thunderbolt and loses faith in him. Later on, Lucky tries to prove that he is brave by climbing up the TV windmill but ends up putting himself in danger instead. Fortunately, Thunderbolt notices Lucky in trouble and, pushing his fears aside, manages to rescue his young fan. Lucky thanks Thunderbolt who tells him that a hero isn't one who fears nothing, but is one who is willing to overcome his fears. Lucky agrees with Thunderbolt and they reconcile.
The One Hundred and One Dalmatians Diamond Edition Blu-ray features a Thunderbolt short based on early drafts of the scene, which follows the events directly from where they are seen in the animated 101 Dalmatians.
The short shows that Thunderbolt and Dirty Dawson are able to catch branches sticking from the side of the waterfall. Dawson is able to reach a ledge and as Thunderbolt's branch is about to snap, his human, the sheriff, is able to use his lasso to save him. The two pursue Dawson, but the thief uses explosives to cause an avalanche, blocking their path and allowing him to take some sacks of money from a wagon, which may be why Thunderbolt is chasing him. The sheriff thinks Dawson has escaped, but Thunderbolt climbs across the rock pile to continue the chase. In the end, thanks to Thunderbolt, Dawson is nabbed and brought to justice.
- Thunderbolt is similar to Flash the Wonder Dog from Chip 'n Dale Rescue Rangers, as both are famous heroic dogs who don't do their own stunts, both of them are German Shepherds, both are the stars of their very own shows, and both are idolized by another animal character (Patch/Lucky for Thunderbolt; Dale for Flash).
- According to the February 2003 edition of Disney Adventures, Thunderbolt's hometown is Powell, Ohio. It also says he has four brothers and sisters, graduated with honors from "Miss Prim's School for Proper Puppy Etiquette", and his first job was doing "Puppy-Krunchies" commercials.
- In the 101 Dalmatians: The Series episode "Frisky Business," when Thunderbolt introduces himself in the "Kanine Krunchies" advertisement, he barks it in a similar style to how James Bond introduces himself.
- While Thunderbolt doesn't physically appear in the video game 102 Dalmatians: Puppies to the Rescue, he is mentioned in a new show entitled Thunderbolt in Space, which is viewed by Oddball and Domino in the intro.