As a Charmander being lifted from its Poké Ball
Green obtained Charizard when it was a Charmander in Professor Oak's laboratory. He chose Charmander to make Red's life easier as Red had trouble deciding which one of the three he wanted. Green tests Charmander's strength over a Clefairy that barged in the professor's lab. Charmander does so by burning Clefairy's tail, which makes the Normal-type run in panic, setting the lab ablaze. Around that time, Green and Charmander already left. After Green quickly caught a whole bunch of Pokémon, Charmander carries a bag of Poké Balls during Green's visit with Red to show him the amount of Pokémon caught. During Clefairy's treatment at the Pokémon Center, Green has Charmander throw a fly in the window to sabotage the process.
Charmander challenges its first Gym battle against Brock's Onix where it was easily taken out by the rock snake. During the search for a Mew that took the Moon Stone Red wanted, Charmander leads Red and the others to an abandoned water mill, as Green wanted to capture the Mew badly. After arriving, Charmander battles Clefairy after Green tries to capture the Mew that Bill's wife transformed into. Clefairy changes into a firefighter which made Charmander laugh. Charmander then evolves directly into Charizard, skipping the Charmeleon stage. Charizard was getting difficult for Clefairy to beat. However, Bill uses one of his machines to shrink Charizard only for Clefairy to get in the shrinking process too. After Bill and his wife changed back into humans, Charizard and the group ran away in fear when Bill's human form was too hideous.
When Red and his Pokémon went to the Celadon Game Corner, Green appears with Charmander who was revealed to have devolved to its basic stage. It played with the slots along with Green, rivaling Red and his two pals. Having enough, they left the Game Corner. Later, Charmander destroyed Red's boat by breathing flames on it so that Green would be way ahead of Red. Charmander evolved again into Charizard sometime before Red and his Pokémon went to Seafoam Islands to search for Articuno. It was still showing a rivalry towards Clefairy. After getting into the end of the cave, it devolved back into Charmander. They managed to find Articuno only for both Charmander and Green to get frozen by the Legendary Bird despite Charmander having the type advantage. Charmander returned as a Charizard briefly where it was carrying Green on its back. Next to them was Blue, Doduo and his Blastoise after they beated Red in getting the flying machine.
Charmander participated in many activities. The first task was the sports meets where it temporarily evolved when it was lifting a heavy Snorlax. Charmander snuck a Voltorb in the ball basket when Magnemite was absorbed onto a big magnet. Charmander did it so that Clefairy could get it instead of an actual ball on purpose. The next task in the sports meet was a special race where it did not win. After the sports meet, Charmander played baseball with Green's other Pokémon where it did not win once again. The third activity was a swim race where Charmander was shown to be a great swimmer.
When Red and the gang were on Cinnabar Island, Green and Charmander were the target of Clefairy hitting them with a bat and hammer. The group go to Blaine's restaurant which turns out to be a Gym in the back room. Charmander and Clefairy become the contestants in Blaine's Quiz Show as their Trainers get strapped to a pod. During the final portion of the quiz where Blaine sent out Arcanine, Charmander watched as it battled Clefairy and both get stuck inside cement. After the challenge in Blaine's Gym, Green and Charmander go to a mansion where Giovanni and Bill were creating Mewtwo. They get caught and tied up by Giovanni afterwards but were freed when Red and Clefairy stopped Giovanni from obtaining Mewtwo.
Charizard and its rival, Clefairy
Green participated in the curry competition with his Charmander and his other Pokémon. Later, they were contestants in a contest that Giovanni was hosting in a dome on TV. In the first part of the contest, Charmander managed to bypass the hidden Muk. In the second part, Charmander went through three Scyther with their sharp blades quickly without getting hit. During the third part, Charmander climbed the ropes across and was successful. In the last part, Charmander got on a race car for the race car derby and no winner was announced since Clefairy destroyed the dome.
Green participates with his Charmander in the New Year's game Professor Oak hosts. Charmander played cards with Red, Blue and Giovanni along with their Pokémon. When Clefairy was about to get a card, Charmander places its tail on Clefairy for amusement. Afterwards, Charmander and the group play Japanese paddle ball where it was caught in the explosion when Clefairy slammed a Voltorb that was mistaken for a ball. Charmander then started laughing at Clefairy when he was drawn a funny face on by Giovanni's Meowth. Ink was then splattered on Charmander when Clefairy and Meowth were fighting. With the fighting over, Charmander and the others go on a ski-race. It was thrown off course by Meowth when Meowth distracted it. After the race, it relaxed in the hot springs with the group, save for Clefairy since he got sent flying to a blizzard.
Later when Red was given a mission to infiltrate Giovanni's mansion, Green and Charmander tag along when they made their aerial entrance. The group go inside the mansion successfully without being caught. Everything went well until they encountered the vault and Giovanni along with Team Rocket run up to them. Charmander trips his Hitmonlee as a distraction so that Pikachu could open the vault. When Charmander and the group went inside, Giovanni and his twin brother close the vault and lock them in. However, the mansion got blown up when Charmander lit up Clefairy's "gas" and sent Charmander and Green flying. They went to a desert where Charmander ended up evolving into Charizard and did not devolve back into Charmander since then. The villagers go to Charizard and ask Green if they want to play the part of the dragon who destroys the village. Green declines and flies away on Charizard. They flew to a vacation spot where they were resting at the beach. Charizard participates in a soccer match with Red and his Pokémon after Green told Red about the match. Charizard decided to intimidate Red's team. In the end, Charizard and all of the Pokémon were attacked by Exeggcute. During the Pokémon League, it was the first Pokémon that was sent out during Green's match against Red. Despite putting up a good fight, it could not handle Clefairy's gag moves.
Following the match, Charizard went with Green and the group to Professor Oak's where they went back in time to discover ancient Pokémon. However, Charizard somehow became wild and was beaten by a prehistoric Red when he threw a rock at it. After their voyage, Charizard and the ancient Pokémon along with the group return to the time machine and head back to the present. It was briefly seen with Green when he, Red and Blue were on the islands to encounter the Legendary birds and their orbs in order to summon Lugia.
Green and Charizard first appeared in Johto at the Ruins of Alph when Red and his Pokémon made an entrance from above. Both sides were trapped and Charizard battled the Unown after the guy from the entrance was commanding them to do stuff. When the building was destroyed, Clefairy brought his clones from the time that they fought Lugia and Green and his Charizard fell down in embarrassment. Later, they participated in the Winter games where they got past many of Red's rivals. When Green battled Clair, his Charizard was chosen to battle the Gym Leader but was brutally beaten.
In the Pocket Monsters BW manga, Green is seen with Charizard in Unova. It fought with Brock's Onix in the Pokémon World Tournament.