Ash Ketchum (サトシ, Satoshi?) is the main dude whose adventures are followed in the cartoon Pok�mon. The Pok�mon trainer Ash from a place called Pallet Town, based on the character from the original game, is the main character of the Pok�mon anime, the Electric Tale of Pikachu manga, and the Ash & Pikachu manga. Like Red of Pok�mon Adventures, he is loosely based on the protagonist of Pok�mon Red and Blue. The names Ash and Satoshi were hard choices for names in Pok�mon Red (and similarly, Gary and Shigeru (named for Shigeru Miyamoto, creator of many other Nintendo franchises such as Mario and Zelda) for Pok�mon Blue). The surname Ketchum is a pun on Pok�mon's now-defunct slogan, "Gotta catch 'em all!" It is possible that he was given this surname to match the number of mouth movements in the anime (Satoshi has 2 more syllables than Ash), so as to make redubbing easier. Ash is voiced by Rica Matsumoto in the Japanese version and currently by Veronica Taylor in the English dub. However, in The Mastermind of Mirage Pok�mon, his dub voice was provided by Jamie Peacock.

Ash often does things without thinking first. He is a typical shōnen hero: very excited, empathic, sometimes focused to the point of distraction, and smart when it comes to his obsessive interest (Pok�mon training, in this case) though often clueless in other areas. He's also very confident and noble, but he can be arrogant and stubborn. Ash also shows impressive endurance, having on several occasions been hit by Pok�mon attacks without suffering any lasting harm, such as being breathed fire on by Charizard and being hypnotized by an Exeggcute, though such events are usually used for comedic effect.

Like most shōnen, he is on a quest; in this case, Ash seeks to become the greatest Pok�mon trainer in the universe. In pursuit of this end, he travels around the world, battling Gym Leaders and entering in Pok�mon League competitions, similar to the protagonists of the Pok�mon video games. He is first accompanied by Misty and Brock, and later on by Tracey Sketchit during the Orange Islands saga, and May and Max in Advanced Generation.

His lifelong rival is Gary Oak who is the same age as Ash. On his tenth birthday, Ash was to receive his first Pok�mon. But he overslept and by the time he arrived at Professor Oak's Laboratory, all the starter Pok�mon (Bulbasaur, Charmander, and Squirtle) had been taken (his original choice was Squirtle, which ironically was taken first by Gary Oak) and he had to start with a Pikachu instead. His Pikachu has the particular characteristic of hating Pok� Balls so it always tags along with Ash. Because of Pikachu's powerful electric attacks, Ash is the frequent target of Team Rocket's plans of stealing Pok�mon for their own interests.

Ash has a reckless streak, as shown in the movies. Ash says that he probably got this streak from his mom. In the first movie, he runs into the path of a pair of psychic attacks fired by Mewtwo and Mew, getting himself temporarily petrified; in the second movie, he runs into electrical cages containing Moltres and Zapdos; in the third movie, he runs into a force field protecting the elusive Unown; in the fourth movie, he runs up the side of a tree after being hit by one of Celebi's attacks and also venturing into "a giant twig monster" to rescue a brainwashed Celebi; and in the fifth movie, Ash runs into a force field that is hurting Latios, Pikachu and Latias, doing likewise.

Ash's mother is Delia Ketchum (or Hanako in Japan). She is a caring, though strongwilled young woman, and (in the English dub) oftens pesters Ash to change his underwear every day, a gag that runs throughout the series. Much speculation exists about the identity of Ash's father, which is officially unknown. One reference to him exists in the Pok�mon anime. During a phone conversation between Ash and his mother in the second episode, she states her amazement that he got from Pallet Town to Viridian City so fast. "It took your father four days to get there when he started Pok�mon training", she says. "He'll be so proud!" In the Pok�mon Live! stage show, it is suggested that Giovanni, the head of Team Rocket, is Ash's father.

It should be noted that for a small time Ash had been turned into a Pikachu by a Pok�mon sorceress by accident near the end of an episode, making him the first human in the anime to be turned into a Pok�mon. The girl made a spell that was supposed to let the receiver see into the mind of a Pok�mon. Ash was eager to be first, since he and his Pikachu helped gather most of the ingredients over the course of the episode; the spell, however, went wrong and he became a Pok�mon instead. This Pikachu version of Ash had messed-up hair (similar to the human Ash) and his trademark hat. His eyes and voice (he was still capable of speech) stayed exactly the same. The next episode, which took place four days later, showed Ash still as a Pikachu, but he reverted to his human self before the plot started.