In the games
Bill is the talented and famous inventor. He invented Pokémon storage system and Time Capsule. People and himself call him Pokémaniac. He has a big collection of common and rare Pokémon. The first one he caught was an Abra. Celio is his old friend that knows lots about him. Bill has many fans like Pokémaniac Brent which calls to the main player with information about him. Bill has a big family. In Fuchsia City lives his adult sister and Bill's grandpa, which in Generation II keeps Bill's Cottage near Cerulean City while he is visiting his hometown, Goldenrod City where his mother and young sister live. One of his sisters can't wink. Bill can't stomach milk.
In Pokémon Red, Blue, and Pokémon Yellow, Bill is found at the Cerulean Cape, initially performing an experiment on Pokémon teleportation. He, however, gets combined with the body of a Pokémon and requires the player's help to fix the problem. After things are back in order, he informs you about his Pokémon Storage System and the "Someone's PC" changes to "Bill's PC." He also gives you the Template:I, allowing you to board the S.S. Anne. Later in the game, you can visit part of Bill's family in Fuchsia City.
While visiting Lanette, players can check one of her computers to find an E-mail from Bill. This is the only time that he is mentioned in the game. However, no such mention is made in the Japanese version (not confirmed with Pokémon Ruby and Sapphire).
In Pokémon FireRed and LeafGreen, Bill is in the same area as in the original games. However, you meet up with Bill on Cinnabar Island after receiving the Volcanobadge from Blaine. From there, you go to the first three Sevii Islands and complete a short side story.
In the anime
Ash, Misty, and Brock meet Bill at his lighthouse in Mystery at the Lighthouse, his Japanse voice actor was Masaya Onosaka, his English voice actor was Maddie Blaustein and his Brazilian Portuguese voice actor was Marcelo Campos.
Bill had previously been trapped in a Kabuto costume for what he claims to have been hours until Ash finally comes to press the release button for him. Afterwards, Bill fulfills a request made by Professor Oak to give Ash and his friends a lesson on the basics of Pokémon, during which Bill shares the idea that there may be many more than just 150 species of Pokémon. The remainder of his appearance is spent focused on explaining to Ash and company his recent project, involving a mysterious Pokémon whose cry can be heard across the sea.
In the TCG
Bill appears on his own card in the Base Set . It allows the player to draw 2 cards from their deck. In the Neo Genesis expansion, he appears on a card called Bill's Teleporter, that gives the player of chance of drawing 8 cards. In the Expedition and EX: FireRed and LeafGreen expansions, he appears on a card called Bill's Maintenance.
In the mangaPokémon Special, Bill serves not just as a scientist and inventor, but as part of the Pokémon Association.
Bill had been dragged into all sorts of misadventures in almost every saga (except for Hoenn and Battle Frontier) ever since he was turned into a Rattata by his experiments and snatched up by a Fearow. His other exploits including helping Red find and capture an Eevee that had escaped from Team Rocket; facing Lorelei in combat with Yellow; fighting alongside Lt. Surge against Bruno on the Cerise Island; and being attacked by a group of playful Staryu after meeting Crystal.
Bill not only designed the Pokémon Storage system, he also maintains it from his home, and was the one who repaired it after the Mask of Ice's Team Rocket sabotaged it, allowing trainers from all over to send their Pokémon to aid Red, Green, Blue, Yellow, Gold, Silver and Crystal in their battle against Ho-oh and Lugia. He also created a portable Pokémon Transfer system using a PokéGear and a Pokédex, allowing Crystal to send Professor Oak the Pokémon she captured while the system was down.
At the end of Volume 15, he is shown working with Daisy Oak, and they seem to be getting along well, hinting at a possible relationship between the two, although there was never any solid evidence provided later.
His Pokémon include Vulpix (which he keeps as a guard "fox"), Magikarp, Exeggcute (which evolved into Exeggutor in the Sevii Island stories) and Farfetch'd. In the Japanese version, Bill speaks with an Osaka accent.
In the first chapter of How I Became a Pokémon Card, a younger Bill rescues a lost Dratini from an angry crowd and it lives with him for a couple of days, until its father, an angry Dragonite, begins to go on a rampage. Dratini returns home, promising to always be friends with Bill.
Bill being mixed with a Pokémon during a teleportation experiment seems to be a direct reference to the movie The Fly, in which a scientist experimenting with teleportation pods ends up combined with a fly.
Bill's name may be derived from Bill Gates, former head of Microsoft.
Professor Oak • Mom • Blue • Daisy • Old man • Bill • Mr. Fuji • Safari Zone Warden • Copycat • Primo
Pokémon Fan Club Chairman • Celio • Lostelle • Teala • Selphy • Cal • Steven Stone • Maylene • Cameron • Mr. Game
Team Rocket • Gym guide • Gym Leaders • Elite Four • Name Rater